Part of an act?

“I am quite a fan of limericks,” says a Craigie reader. “One of my favourites is a little ditty which goes like this: “I passed by your window

One morning at three.

Please tell me what was it

You emptied on me.

“Does anyone recognise it? It could have been part of the act of some comedian who suddenly introduced such snatches of song into his act to keep the audience on their toes.”