triple penetration
A sexual situation usually involving a female whose three major orifices (mouth, vagina and anus) are being penetrated by penis, tentacles, clenched hand, dildo or other inanimate object... or perhaps some combination of the above. May occur together with spitroast and group sex.
Could theoretically involve a male on the receiving end, although the third orifice might imply an earjob or guro.
Also see double penetration.