a flap of skin is a large piece of really thick skin that is in place of someones genitals and can be used as a means to cool people down by waking there flap of skin about, mostly found on males who watch animee and like to shove rats up there arse and then eat them.
oh my god did you see ronan shoving rats up his arse while liking his flap of skin.

yeh it was disgusting, it made me want to cut my face.
by PACHOWW May 10, 2009
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