A form of group sex involving exactly three people at the same time.
A threesome is not an orgy or a gangbang. An orgy involves multiple couples of groups or people having sex. A gangbang is three or more people having sex with a single person.
For the purposes of threesome tags, futanari are not counted as "female", but as "D" (dickgirl) instead. Likewise, cuntboy and male futanari are counted as "C" (cuntboy).
