Wiktionary
spintrian
a. Of or pertaining to sex or fornication (especially homosexual) between three or more people.
Usage examples of "spintrian".
For there are certain tempers of body, which, matcht with an humorous depravity of mind, do hatch and produce vitiosities, whose newness and monstrosity of nature admits no name: this was the temper of that Lecher that fell in love with a Statua, and the constitution of Nero in his Spintrian recreations.