Someone had sex on our stage while we were playing

There was a big club we used to play at in a very “touristy” town. The stage was VERY big and had black curtains all around it.

This particular night there was a big stack of risers to the right and ON the stage.

Apparently a female patron of the bar and one of the bar tenders climbed to the top of this stack of risers and “got it on” while the band was playing in front of 900 people.