When people fuck like animals. Having some savage ass sex, like non-stop penetrating action. When two or more people just fuck past morning light into the next night. When 2 or more people turn into a beast in bed. This generally happens after a person goes several weeks or months with out sex.
Yo Jack and Jane fucked like Monkeys, they just fucked, and fucked, and fucked.
When a female has a huge ass, i'm not talking about a weak, scrwany, undernourished anerexic ass, i'm talking about a big, fat, jiggly, round booty.
IT got it's name, by mimicking the sound an ass makes from a distance (when you check one go by, in slow motion, it goes, Badonk-a-donk).
Damn Yo, that quite possibly is the biggest ass i've ever seen, that's not just an ass, thats a badonkadonk, i want a piece of that.