An exercise in which one sprints the length of a football field, dropping at the marked 5 yard intervals to to a push-up. Typically belly flops are assigned as a punitive measure.
Football coach - "Alright, since you clowned around so much during the game that we lost, you get to do belly flops right now until I get tired!"
football team "Aww fuck man, this is gonna suck..."
The belly flop is a promiscous act in which the female is getting railed from behind, the male tells her that he is done, whips it out, and blows it on the bed, couch, what have you. As soon as he does so, he sticks his hands between her legs, and knocks her arms and legs out from underneath her, causing her to take a big belly flop.
The 200 something pound Guy who makes a mark for only doing BELLY FLOPS OF THE "DIVING BOARD" and piwers through the Red marks he gets and does it more than twice. He also gets praised for doing the Belly FLOPS and lowering through the Big RED MARKS he gets.
Did you see Belly Flop Man he is being so awesome, he's doing BELLY FLOPS for our amusement I love him. I wish I had the coujrage and confidence he has.