a set or pair of hang down vaginal lips that are larger than normal. to be true 'boston bat wangers'; they must hang low/long enough to wrap around a penis
Origionally coined in the mid 90's on bullitin boards to describe photo's of a girl on her back that had droopy boobers. They where out to the sides swinging like wings and she prolly shouldn't be in pr0n.
"Bat Wangers"