The past tense of the word "flaw", which is an adjective used to describe a person who just bailed, or frequently bails, on commitments. This especially applies to flaking out on social plans, such as going to clubs, theme parks, the movies, concerts, and going on dates.
Flossed : the art of having welcomed a penis in your mouth so deeply that you can go no further, thereby flossing your teeth with the curlies. It’s a win win.
Dude 1: Dude, hey, did Summer serve you up some head last night?
Dude 2: Dude, totally—she totally flossed me, bro
Dudes 1 & 2: hahhhahaaaa