v -to penetrate the vulva; the act of having sex; coitus
a way to refer to sex while in mixed company as it sounds like involve, involved or involvement, but is an available reference to the discerning ear.
Joe, Moe and Flo sitting at burger barn:
Joe -"Why didn't you guys call me back last night?"
Flo *shuffles uncomfortably* "Um, we didn't hear the phone. We were, um, watching a movie."
Moe *winks* "Yeah, I was invulved with other things."