when a heavier woman (almost alway young or pretending to still be young) wears her low rise pants to tight and her baby doll tee is way to short, the tummy flab that spills over the front of her pants and hangs out from under her tiny tee shirt. It looks like a clam lip hanging out. Its like muffin tops but the front view. Sometimes a woman can have a muffin top and a clam lip. or just a clam lip-no tops.
Men can have a Manclam, we have all seen it. its the opposite of plumber butt.
Harry: Oh shit, that girls clam lip is hanging out!
Sally: she even has her pearl out! (belly button is showing)