A scat fetish manuever in which one partner falls asleep facing down, and the other partner lays a long "log" down the ass crack between the two "buns". So awaken to a big "SUPRISE!" (a.k.a. Bun length)
Side note: Top it off with your parnters favoritecondiments for added flare!
When a couple is doing a sixty-nine and the man squeezes his legs together tightly and forces a lumpy dump through the front of his legs and it pushes past your balls into the face of the chick.