a male or female sex friend whom is viewed by others as the complete package, but to you she's strictly used for sex and "flossing" to your friends and/or making other females jealous. (Because we all know how girls get when they see some competition)
Note: Only a true mack can acquire a floss-piece
Dan: Hey, did you see that girl I brought over to Rachel's last night?
Brad: Yeah, what's the deal with her? Are you two dating?
Dan: Haha, naw. She's just my weekend floss-piece.