(v.) the act of placing your hand between someones legs from behind, and flopping your hand under their balls like a flounder, but not actually touching their balls, that would be gay unless "no homo" is called. Usually results in a startled reaction from the individual it is applied to.
Flounder, Floundered, Floundering
Person 1: "Dude why does Marlon look so bummed?"
Person 2: "Ohh, i just floundered him and he was so surprised that he pooped a little and it dripped down his legs onto his sock. Those are new socks."
Person 1: "Ohh that sucks, at least he gives good LJ's and can move silently through the night"