Past tense: When three people get together and throw up into one another's mouths for purpose of sexual arousal.
Steve to Phil: "Hey Phil! Were you part of that threwsome I heard about last week?"
Phil to Steve: "Nah man, I'm more of a scat guy myself..."
Phil to Steve: "Nah man, I'm more of a scat guy myself..."
by xXthedirtydonXx November 18, 2016
Get the threwsomemug.