To be penetrated anally (particularly males) with a baked dough phallus. Buttinos are usually found in the wild at lengths of 12-18 inches (don't act like you're not impressed), and can grow to be as large as three feet if you're really adventurous. Variations can include items such as black olives, alfredo sauce (great for simulating semen!), tomatoes (open sores, you know what that's like) and spaghetti noodles often symbolizing pubic hair.
Andrew's butt was sore this morning because he was Buttinoed all night long.
Friend A: "That girl's so hot!"
Friend B: "Yeah, but I hear that Stephen Buttinoed her until she bled last night. Dirty."