The act of having sexual intercourse with two women at the same time. In order to facilitate this a man wears a strap on backwards while positioning one of the women in front of him and one behind him. He then proceeds to move back and forth, similar to the motion of a pendulum.
Wow those twins have been hanging out in your room a lot lately whats the deal? What can I say, they can't get enough of the Carolina Pendulum.