What a fat person disappears into when she is out with her friends of 'normal' weight, & she suddenly gets the urge to go home & hide from the world because she feels SO fat next to her friends. This necessitates coming up with a plausible excuse to be able to leave.
Girl 1: Hey. Where's Kel? Wasn't she standing there just a moment ago??
Girl 2: She left. Said her cats needed feeding or neutering, or something.
Girl 1: I see. Guess she disappeared into fat air.
A gathering of females much like a bachelorette party, except there isn't 1 bacholerette whose 'freedom' is ending. Girls may or may not come in 'sexy' attire & sex toys are brought. A hired expert teaches how to give blowjobs, how to stimulate the clit, etc. At the end of the night, party favors may be handed out (edible underwear, etc). The most famous bad girl party in a movie would probably be that one from Old School with (Luke Wilson, Will Ferrell, etc).
girl 1: shanna's bad girl party was stoke! you shoulda been there, there were contests & in the last 1, the prize was...ready for this?? a jack rabbit vibrator!!!!!
girl 2: *screams* zOMG!!!!!