Sodomy. The detestable crime of having commerce contrary to the order of nature by mankind with mankind, or with brute beasts, or by womankind with brute beasts (i.e. the 'pony-shows' allegedly formerly? available in Tijiuana or Baltimore's 'Block'), or by mankind with womankind through anal intercourse [aka 'pumping the poop-chute,' 'entering the back door,' 'going down the dirt road,' 'butt bumping,' 'ass-f**king,' etc. - Note: These are generally not considered proper or acceptable legal terms and therefore it may be wise to avoid their inclusion in most formal court filings whenever possible.]
Depending on the specifics, this often was, and can still be, a highly penal (and usually penile) offense.
The origins of the term are unclear but, according to the Library's Head Librarian's research, may derive from supposed, all-but-forgotten, religious sexual intercourse rituals involving humans and insects [aka 'bugs' hence the term] allegedly practiced and/or encouraged by some rather peculiar early Catholic Popes and other church officials. Despite no evidence that such practices continue to the present, this has not yet been substantiated or denied by reliable church sources, a fact our Head Librarian considers highly suspicious.
Also see: sodomy, bestiality.