The few seconds during a porno, or sexy scene in a movie that just kills your erection dead. Either the camera cuts to the hairy cum-face of the man, some pet or animal comes on set, or something particularly gross happens, killing the mood.
'Ah man did you watch 'horny home alone amateurs 11'? I was just about to shoot my load when her dog comes in the room and starts barking, fucking flopshot should have been edited out.'
The Act of a man laying behind a woman in bed while trying to fall asleep when suddenly the man pulls out his erect penis and flops it at the lower back of a woman in an attempt to arouse her sexually and if the clothing (or lack there of) is right he may even be able to flop it right into her vagina.
Dave: So I was layin' down with Felecia last night and I totally gave her the flop shot!