the term 'beef flaps' is used in a derrogatory fashion to describe the female genitalia, as they tend to, (especially when a female is aroused) resemble two peices of flappy beef, between the legs of the woman.
'look at doreen's beef flaps, i bet you a tenner she hasnt shaved them in at least three weeks!'
its the bit that likes to hang around between a blokes legs, between his balls and his bellybutton, unless he's weird and deformed in case you should probably stop looking.. or asking for that matter. freak.
Cyril nearly knocked Wendy out with his luncheon truncheon as they ran naked through the field...