The tag alias #72062 piv -> vaginal is pending approval.

Reason: this is what it means

this sounds like it's supposed to be a shortening of "penis in vagina" wouldn't a -> penis_in_pussy alias make more sense?

It's not always penis_in_pussy. It's not even always vaginal:
post #4488072 post #1971903
Some I'd argue should be ambiguous_penetration rather than vaginal:
post #1747126 post #3771183 post #4627892

It also seems like it could be a typo for pov. There's also Pivv as a character's name. I could see Piv itself also being a name.

Has this ever been used here?

versperus said:
Has this ever been used here?

9 times in the last 10 years, last used 6 months ago.