A woman who possesses co-dependant traits and is both possessive and controlling with regards to the men she dates. The male gender's underlying assumption is that said woman's boyfriend remains in this unhealthy relationship due to the sexual gratification the female provides, specifically, fellatio.
A common turn of phrase pertaining to this is "He's being whipped", which means that the person in question is being dominated or controlled, historically represented by a whip, which was used to drive slaves.
When a man dating a woman with whip lips has his girlfriend/wife overtly make a controlling gesture or demand, verbally or otherwise, friends in or near the occurrence often make a whipping sound, such as *Wha-chu*, immediately after said girlfriend is out of earshot to denote the fact she has whip lips.
Also jokingly referred to as Whipelipsy, a play on the disorder known as Epilepsy.
John: I'm going out on a date with Tina tomorrow.
Frank: Watch out man, that bitch has got whip lips.
the numbness, chapped-ness, peeling etc of lips after doing whip its straight out of the cracker
Her whip lips were really bad, they started to bleed. I told her to stick with the balloon.