Wickerslam

A sexual act involving three dicks being inserted into three holes. While possible between humans, the act was designed for a kangaroo and three monkeys, as kangaroo females have three vaginas and monkeys are flexible.

Originated from Seussical the Musical, which features a kangaroo and three monkeys named the Wickershams battling some obvious sexual tension.

Doesn't have to be rape, but it helps.