When you take your hand and make it into a beak shape by clenching your fingers together. Then use it to pleasure your own or a friend anally
“I met this hot girl, can’t wait to suprise her with a Buttbeak”

Friend - “what are you up to tonight?”
Friend 2 - “Not much, might hit the town and do some buttbeaking”

(Sung with a best) “If you want to Buttbeak like a Pro, use plenty of Lube and take it nice and slow”
by Sam Liquorson February 25, 2019
Get the Buttbeak mug.