The sexual act where
one defecates on a partner's
face, then proceeds to rub said faecal matter into the
face with a back and forth motion of the buttocks. The buttock cleavage should form a groove into which the nose slots, providing a guide for this motion.
This was allegedly the act to which Meatloaf referred to in the iconic song lyric: "I would do anything for love, but I won't do that".
Jim: "Hey
Randy, you know what Meatloaf wouldn't do for love?"
Randy: "Don't tell me, galleoning?"