A polite reference to someone in the next room having crazy loud monkey sex. Grunting and bedsprings are often heard coming from the walls. People who engage in babooning do not care if others can hear them, and often will only stop if you repeatedly bang on the walls and yell at them
*grunting noises from next room*
person 1: URGH! Their babooning again
person 2: I'll the ear plugs and you start banging on the wall