anal sex
Enable an AI agent to recognise an anal-sex episode, record its boundaries and current state, and determine which documentation, consent checks or support actions are appropriate.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise an anal-sex episode, record its boundaries and current state, and determine which documentation, consent checks or support actions are appropriate.
Anal sex is sexual activity in which the anal canal and distal rectum are used as a receptive sexual orifice - classically by the penis, and by extension by a finger, tongue, or object - whose clinical profile is set by the internal and external sphincters, fragile non-keratinized rectal mucosa, and the lack of vaginal-type lubrication.
It can be Classify a reported activity as core anal penetration, a boundary case or a neighbouring activity.; Separate an encounter into anal-contact segments when means, roles, consent or conditions change.; Identify missing or withdrawn agreement and suspend any assumption that continuation is permitted.; Record contact sequences and reported barrier changes for an appropriately authorised assessment.; Capture a pause, stop or request for support and route health questions to a separate clinical workflow.; Produce a minimal, access-controlled episode summary that preserves uncertainty and participant attribution..
Distinguishing features
Intentional or reported penetration of the anus in a sexual context distinguishes the core episode from nearby genital contact without anal involvement.
Anal penetration during a clinical examination or procedure is excluded unless a separately identifiable sexual episode is being described.
Penile, digital and device-mediated penetration must be distinguishable rather than inferred from the label alone.
Oral-anal and external anal contact must be recorded separately from penetration, with their membership in this registry concept left explicit.
The activity label does not establish consent, participant gender, sexual orientation or relationship status.
Scope
+ Whether anal penetration is intended, attempted or reported, and how non-penetrative contact is classified
+ Episode boundaries, participants and act-specific roles
+ Each participant's capacity, voluntary agreement, limits and changes of consent
+ Reported contact routes, barriers, lubricant use and changes between anatomical sites
+ Reported comfort, interruptions, completion and requests for follow-up
- Sexual orientation, gender identity and enduring relationship classifications
- Standalone models of oral sex, vaginal intercourse and non-penetrative sexual activities
- Clinical diagnoses, examination findings and treatment protocols
- Product specifications for condoms, lubricants and sexual devices
- Jurisdiction-specific legal determinations and investigative case management
- Explicit sexual coaching or erotic descriptions
Characteristics
- Episode state
- proposed | agreed | started | paused | stopped | completed | unknown Distinguishes an intention from an event and prevents a previous agreement from being treated as ongoing permission.
- Anal contact category
- penetrative | attempted penetration | external contact only | oral-anal contact only | unclear Supports recognition of the core concept and exposes disputed boundary cases.
- Penetration means
- penile | digital | device-mediated | other reported means | none | unknown Prevents the generic label from concealing materially different acts.
- Participant role by segment
- participant linked to receiving penetration, performing penetration or self-directed activity within a particular segment Allows roles to change and avoids assigning permanent identity labels.
- Consent for the specific segment
- affirmatively reported | conditional | uncertain | withdrawn | absent | not recorded, separately for each participant Makes permission specific to the act, means and conditions rather than the encounter as a whole.
- Barrier and lubricant configuration
- reported type, placement and use; changed | unchanged | failed | unknown where applicable Preserves relevant conditions and changes without treating their presence as proof of safety.
- Anatomical contact sequence
- ordered links between body part or device, contacted anatomical site and barrier configuration Distinguishes the anal segment from other activities and records transitions relevant to later assessment.
- Participant-reported physical response
- comfortable | discomfort | pain | bleeding | other reported symptom | unknown, with participant wording and timing Supports interruption and follow-up decisions without converting observations into diagnoses.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Anal act identity Establishes which anal activity is described and whether it belongs to this entry.
The registry name alone does not resolve penetration means, non-penetrative boundaries or sexual versus clinical context.
Contact and means
Identifies the anatomical contact and the reported means of penetration.
Penetration classification
Records intended, attempted or reported anal penetration separately from external or oral-anal contact.
- Was anal penetration proposed, attempted or reported to have occurred, or was contact exclusively external? definition
- Which means of penetration were reported, and which details remain unknown? measurement
Context and neighbours
Separates this sexual activity from adjacent acts and nonsexual procedures.
Registry boundary
Makes the reason for inclusion explicit without using consent or participant identity as a substitute for act classification.
- What reported context distinguishes this episode from an anal examination, treatment or other nonsexual activity? boundary
- Does the description include oral-anal or external anal contact that needs a separate classification or an unresolved-boundary flag? boundary
Participants and permission Records participants' segment-specific roles and the conditions under which participation is agreed.
Agreement to an encounter or another sexual act cannot stand in for agreement to the particular anal activity.
Roles and capacity
Connects each participant to the anal segment and records whether valid agreement can be established.
Participant position
Tracks receiving, performing or self-directed roles alongside unresolved capacity or safeguarding concerns.
- Who receives or performs penetration in this segment, and is the activity partnered or self-directed? definition
- What information establishes or leaves unresolved each participant's capacity and freedom to agree, including age-related safeguarding concerns? provenance
Specific agreement
Records agreement and limits for the particular means and conditions of anal contact.
Permission and withdrawal
Preserves each participant's stated limits and any subsequent uncertainty or withdrawal.
- What agreement was expressed for this anal activity, including penetration means and any required barrier or other condition? provenance
- Has any participant withdrawn agreement, expressed uncertainty or indicated a limit that requires the activity to pause or stop? action
Contact conditions Describes reported barriers, lubricant use and movement of contacting body parts or devices.
An undifferentiated anal-sex label omits conditions needed to interpret the episode or refer a concern for assessment.
Barriers and lubricants
Captures what was reportedly used and whether its condition changed.
Reported contact configuration
Records barrier placement and integrity and lubricant identification without asserting compatibility or protection.
- Which barriers and lubricants were reportedly used for the anal segment, and which product details are unknown? measurement
- Was any barrier breakage, slippage, removal or replacement reported, and when did it occur relative to anal contact? measurement
Site and device transitions
Tracks contact changes involving the anus, other anatomical sites and shared devices.
Contact sequence
Preserves the sequence of contact and reported changes between segments for later interpretation.
- Did a contacting body part or device move between the anus, another anatomical site or another participant? measurement
- What cleaning, barrier replacement or device replacement was reported at each transition, and what remains unrecorded? provenance
Episode course and response Tracks the anal activity's progression, participant feedback and reasons for interruption.
An episode's current state depends on what occurred and what participants report, including changes after initial agreement.
Segment lifecycle
Separates planning, attempted penetration, active contact and the end of a segment.
Progression and stopping
Records transitions without treating attempted penetration as completed penetration or a pause as permission to resume.
- Which anal-contact segments were proposed, attempted, started, paused, stopped or completed? measurement
- What change in consent, means, participant role or contact conditions requires a new segment or a renewed permission check? action
Comfort and symptoms
Captures participant-reported responses during and after anal contact.
Response and support
Keeps reports of comfort, pain, bleeding or other concerns distinct from inferred injury or diagnosis.
- What comfort, discomfort, pain, bleeding or other symptoms were reported, by whom and at what time relative to anal contact? measurement
- Has a participant requested stopping, practical support or clinical assessment, and what response remains outstanding? action
Sensitive record and follow-up Controls the evidential meaning, disclosure and onward use of the anal-sex episode record.
Recording this activity can expose intimate information, while ambiguous reports can be mistaken for confirmed conduct or medical conclusions.
Attribution and minimisation
Retains only justified anal-act details and identifies their source.
Account status
Distinguishes a participant account, third-party report, hypothetical scenario and agent inference.
- Is each claim about anal penetration, consent or contact conditions a direct account, a third-party report, a hypothetical statement or an inference? provenance
- Which intimate details are necessary for the authorised task, and which can be omitted or generalised? action
Assessment handoff
Connects unresolved concerns to appropriate neighbouring models without embedding clinical or legal conclusions.
Follow-up boundary
Records requested follow-up and the minimum relevant episode information needed for an authorised handoff.
- Does the unresolved concern involve symptoms, reported exposure, consent or safeguarding, and which neighbouring workflow owns its assessment? boundary
- What disclosure is authorised, to whom, and which timing and anal-contact details are necessary for that specific follow-up? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Penile-anal intercourse (insertive or receptive role)
- Anilingus (oral-anal contact)
- Digital anal penetration
- Anal penetration with a sex toy or other object
- Pegging (typically strap-on penetration of a partner)
- Anal fisting
- Solo anal masturbation
- Condomless anal intercourse (public-health / HIV-epidemiology category)
- Which of these kinds and varieties hold for the sense of anal sex this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q34162 - Item commonly labelled 'anal sex' (the sexual practice).
- MeSH - D000071617 - Heading 'Anal Sex' (introduced 2017); maps the practice in biomedical indexing.
- Which of these identifiers and schemes hold for the sense of anal sex this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- US Public Health Service clinical practice guideline for HIV preexposure prophylaxis (PrEP) - Centers for Disease Control and Prevention (condomless anal sex is a specified PrEP indication).
- Lawrence v. Texas, 539 U.S. 558 (2003) - Supreme Court of the United States (consensual adult sodomy may not be criminalized).
- Sexual Offences Act 2003 - Parliament of the United Kingdom (recast non-consensual anal penetration as sexual assault and equalized age of consent; ended the older 'buggery' charging frame for consenting adults).
- Navtej Singh Johar v. Union of India (2018) - Supreme Court of India (consensual adult same-sex acts, including anal sex, read down from IPC section 377).
- Consolidated key-population HIV/STI guidelines - World Health Organization (rectal screening, condoms/lubricant, PrEP).
- DSM-5-TR (American Psychiatric Association) and ICD-11 (WHO) do not classify consensual anal sex as a disorder; paraphilic or assault codes require distress, harm, or nonconsent.
- Remaining 'sodomy', 'buggery', or 'unnatural offences' statutes in a number of jurisdictions still criminalize the act or same-sex forms of it - national criminal codes (not a single issuing body).
- Which of these standards and regulation hold for the sense of anal sex this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Partnered sexual repertoire among heterosexual, bisexual, and gay people; reported as a minority-but-common lifetime practice in high-income general-population surveys (Natsal, NSSHB).
- Dominant exposure in HIV, gonorrhoea, chlamydia, syphilis, and mpox epidemiology among gay and bisexual men who have sex with men; drives rectal NAAT screening and PrEP/DoxyPEP eligibility.
- Clinical sexual-health counselling: external/internal sphincter relaxation, water- or silicone-based lubricant, condom choice, and pain as a stop signal.
- Pornography production and consumption, where the act is a labelled genre.
- Forensic sexual-assault examination when non-consensual anal penetration is alleged (anal canal/rectal injury, swabs, DNA).
- Emergency presentation for retained anorectal foreign bodies after object play.
- Which of these real-world use hold for the sense of anal sex this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Per-act HIV acquisition risk, unprotected receptive anal intercourse with a viremic partner - about 50-170 (point estimate commonly cited 138) - infections per 10,000 acts
- Per-act HIV acquisition risk, unprotected insertive anal intercourse with a viremic partner - about 4-14 (point estimate commonly cited 11) - infections per 10,000 acts
- Anatomical length of the anal canal (surgical/anatomic) - 2.5-4.0 - cm
- Lifetime reporting of heterosexual anal intercourse in large high-income probability surveys - roughly 10-40 (varies by cohort, sex, and question wording) - % of adults
- Which of these typical measurements hold for the sense of anal sex this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Mucosal tears, anal fissure, and rectal bleeding from inadequate arousal, insufficient lubricant, or force against a closed sphincter.
- Higher per-act transmission of HIV and several STIs than typical vaginal intercourse, because rectal mucosa is thin, vascular, and easily abraded.
- Condom breakage or slippage from high friction when lubricant is absent, oil-based lube is used with latex, or the condom is not designed for anal use.
- Anodyspareunia (pain with anal penetration) and avoidance; pain is a clinical warning, not a normal endpoint.
- Sphincter stretch injury and faecal incontinence after extreme dilation (large objects, fisting) or traumatic assault.
- Retained anorectal foreign body requiring endoscopic or surgical removal.
- Enteric bacterial infection and, with oral-anal contact, faecal-oral pathogens (e.g. hepatitis A, shigella, amoebiasis).
- Criminal prosecution, blackmail, or violence in jurisdictions or communities that still treat the act as illegal or stigmatized.
- Which of these failure modes and hazards hold for the sense of anal sex this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Legal name and status: clinical 'anal intercourse' versus statutory 'sodomy' or 'buggery'; still criminal in parts of sub-Saharan Africa, the Middle East, and the Caribbean, while private consensual adult practice is lawful across most of Europe and, in the US, after Lawrence v. Texas.
- Role language: in some Latin American and Mediterranean same-sex cultures the insertive/receptive ('activo/pasivo') distinction is a stronger social identity than a gay/straight binary.
- English internet slang ('pegging', 'rimming', 'ass play') does not map one-to-one onto clinical or legal terms and is not universal across languages.
- Survey prevalence and willingness to report vary widely; Western surveillance over-represents MSM anal sex as a public-health object, while under-reporting is likely where the act is taboo or illegal.
- Some legal systems historically set a higher age of consent or a separate offence for anal sex than for vaginal sex; several (including the UK) later equalized this.
- Which of these regional variation hold for the sense of anal sex this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Vaginal intercourse - Different orifice and epithelium (vagina is a lubricated, stratified mucosa with a different microbiome); per-act HIV risk is substantially lower than receptive anal intercourse in the same source estimates.
- Anilingus - Oral-anal contact without (typically) penile or object penetration of the anal canal; overlapping enteric-pathogen risk, much lower mechanical trauma and HIV risk.
- Sodomy (legal/religious category) - A juridical or theological class that in many codes also covered oral sex, bestiality, or any 'non-procreative' sex; not coextensive with the anatomical practice.
- Digital rectal examination or anoscopy - Same anatomy, diagnostic or screening intent, clinical consent and technique, not a sexual act.
- Clinical prostate massage - May mechanically resemble digital anal stimulation of the prostate but is performed as a urological procedure with a therapeutic or specimen-collection aim.
- Non-consensual anal penetration (anal rape) - The same anatomy and injury pattern can occur; the separating test is consent and criminal-law elements, not the orifice used.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of anal sex this model covers, and on what evidence? provenance
Sources
- Estimating per-act HIV transmission risk: a systematic review - Patel et al., AIDS (Lippincott; CDC authors), 2014 - Per-act HIV transmission probabilities for receptive and insertive anal intercourse used in counselling and modelling.
- HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention - Baggaley, White and Boily, International Journal of Epidemiology (Oxford University Press), 2010 - Elevated per-act and per-partner HIV risk of anal versus vaginal intercourse; insertive vs receptive difference.
- Changes in sexual attitudes and lifestyles in Britain through the life course and over time: findings from Natsal - Mercer et al., The Lancet, 2013 - Population survey evidence that heterosexual anal intercourse is a non-rare reported practice in Britain, with cohort change over time.
- Sexual behavior in the United States: results from a national probability sample of men and women ages 14-94 - Herbenick et al., Journal of Sexual Medicine (NSSHB), 2010 - U.S. probability-sample reporting of anal sex by age and gender in the general population.
- Lawrence v. Texas, 539 U.S. 558 (2003) - Supreme Court of the United States - U.S. constitutional holding that consensual adult sodomy statutes are invalid; landmark legal status of private anal sex.
- Consolidated guidelines on HIV, viral hepatitis and STI prevention, diagnosis, treatment and care for key populations - World Health Organization - International clinical framing of anal sex as a key exposure for HIV/STI prevention, rectal testing, and PrEP in key populations.
What the second pass must settle
- Does the authoritative registry intend anal sex to include digital and device-mediated penetration, self-directed activity, external anal contact and oral-anal contact?
- Does an existing Vercy world model already own this concept or any proposed bundle, requiring a link instead of a duplicate model?
- Which evidence standards and jurisdiction-specific rules should govern capacity, age-related safeguarding and consent-state assessment?
- Which clinically validated criteria should a separate health model use to assess reported symptoms or exposures, and what minimum episode information does it require?
- What retention, access and disclosure rules apply to intimate episode records in the intended deployment context?