Other subreddits which clearly violate Reddit's policy on violent content quoted below yet strangely [as of 2024/01/18] persist nonetheless: /r/Roughanal /r/DegradingHoles
"Do not post content that encourages, glorifies, incites, or calls for violence or physical harm against an individual (including oneself) or a group of people…"https://web.archive.org/web/20230719232538/https://support.reddithelp.com/hc/en-us/articles/360043513151
Also relevant: "Note that health misinformation, namely falsifiable health information that encourages or poses a significant risk of physical harm to the reader, also violates the Rule."
For far too many years now the subreddits mentioned above have been encouraging, glorifying, and inciting anorectal violence in particular that arguably should easily constitute severely criminal behavior when more than one person is involved (at the very least for potentially-lethal outcomes/sequelae). Perhaps people at high levels of Reddit should be held accountable: not only for failing to uphold their own site's policies, but also for enabling the spread of very dangerous violent behavior along with health-harmful falsehoods and omissions facilitating it on subreddits such as /r/sex.
Traumatic risks of human anoreceptive activities include inflammation; abrasion and tearing; muscle and connective tissue damage; and colorectal perforation. Sequelae may arise, such as hemorrhage/hematoma, hemorrhoidal disease, ulceration, bacterial infection followed by abscess / fistula / life-threatening systemic sepsis, rectal prolapse, fecal incontinence, anal skin tag (remnant of external hemorrhoidal thrombosis, scar tissue from a healed tear, or a sentinel tag for a chronic anal fissure), and anatomic stenosis (narrowing due to constricting scar tissue). One instance of trauma can lead to multiple complications. Cumulative damage and preexisting conditions are concerns too.
~2cm beyond the anal opening at the pectinate/dentate line, the epithelium transitions from stratified squamous (anoderm) to simple columnar in part of the narrow surgical anal canal, continuous with the rectum. This very fragile mucosal lining is easily damaged especially if its mucus barrier is removed by an enema or otherwise impaired. Furthermore, some enemas and lubricants can inflame the lining and even cause it to slough off. Since injury to anorectal mucosa alone is painless due to a lack of somatic innervation, resultant problems may remain undetected with no obvious symptom(s).
Neuromuscular physiology also contributes to anorectal fragility particularly for girthy and vigorous insertions, which are objectively foolish and very likely to be significantly injurious. The involuntary internal anal sphincter relaxes with rectal distension. The puborectalis and external sphincter completely relax when a person bears down, causing hemorrhoidal cushions to engorge and become more susceptible to being injured by frictional sliding, aka shear. The internal hemorrhoidal cushions lack somatic innervation as well.