somebody who has nothing better to do than to go home, lay on his bed, bored, and flap his penis around with his two hands continuously because he has no friends, or anything to do.
"dude do you think that moonster kid has any friends"
"who nathan? are you fucking serious man? hes such a dick, of course not, he probably just goes home every night and flaps his penis around out of boredom"
"what do you expect, hes a fucking dick, thats what he gets, and have you seen his clothes?"
"or his hair? i mean its like he WANTS to be a penisflapper..."
An individual who participates in the act of flapping ones penis.
"That penis flapper over there is scaring all the children"