when a woman is being tag-teamed by two guys, one doggy-style and one in her mouth, the man from behind pulls out to spuge on her back. as this happens with a cock-filled mouth, the woman moans and groans (sounding like a monkey) as she has her arms in the air, trying to slap the goo off of her back. hence, sounding and looking like a monkey.

Literally everyone, ever. Including the writer of this definition.