When you take your finger and rapidly Flick your partners titties. THIS WILL HURT. Also this can be done girl to guy. Just flick the dick SOOOPER HARD!
and dont forgot to bring chili soup. It is essential.
Ryan: "When I went to Derricks house I saw him pulling a FlingyBoob on his MOM!!!"
Dan: "Was it Hot?"
Ryan: "He did one on me after!"