What happens when get an erection and your pants fall down at your hot 6 year old sister's birthday party. Also see; Incest
Mom: who's up for cake?
You: *thinking to self* god i am so horny
Mom: blow out the candles sweety
You: *thinking to self* she can blow out my candle anyday
Then your pants fall down, causing everyone to immediatly stare at your giant pulsating penis, you then proceed to turn this occasion into a partyfuck.
when one engages in sexual intercourse with a drunk person they meet at a social gathering either at said social gathering or immediately thereafter.
credit completely goes to syn of EF FAME!!!
"i got a safety buzz so it would cover for any partyfucking that happened later in the night"
"yeah man, i went to that kegger, hit on a chick all night and then i partyfucked her"