A guy who fucks a loaf of bread and then fucks his girlfriend who has celiac disease. Celiac disease is an intolerance to gluten and wheat related foods that can be deadly. The term is possibly referred to in the Frank Zappa song "Broken Hearts are for Assholes."
1. Verb--The act of violently and repeatedly slapping someone in a backhand, then forehand, then backhand fashion (the hand "buttering" the face/"bread"); can also be used to refer to someone being owned. Pseudonyms include B&B, Country Crock on Texas Toast, Land O' Lakes on Wonderbread, etc.
I saw these girls catfighting, and one of them jumped on the other and straight bread and buttered her!