Person, that (freshly) got shot down; derived from the denim brand "Red Monkey", that's currently popular amongst the rap community...
"...leavin' eight niggas bloody, when I'm call 'em red monkey..." (extract of 40 Cal.'s part of "Gettin Money" from The Diplomats feat. J.R. Writer & 40 Cal.)
When you are engaging in sexual intercourse and your partner is hitting it from behind, your asshole prolapses while your partner slaps your ass aggressively so your ass looks like a baboon’s ass.
If you want to spice it up beat the flaccid penis until it is red and stiff.