Monitor and Merrimack

A sexual act where two people adorn themselves in plate mail armor (or many cast iron skillets if on a budget) and throw bowling balls at each other.

The name is a reference to a naval battle in the American Civil War where the first two ironclad ships fought to a draw in a very sexy battle.

"Myself and my second-favorite harlot, Margaret, engaged in a rousing round of Monitor and Merrimack last evening."