A bum gets on a bus, drunk as a skunk. He sees a nun sitting at the back and staggers over and sits next to her.

"Wow!" he slurred. "What a beauty you are! Get that habit off so I can shag you!"

The bus conductor walks up and drags the bum away. "That's Sister Mary", he explains. "She rides this bus every day. You can't talk to her like that, she's a fucking nun!"

"Yeah, but she's the finest piece of ass I've ever seen. I want her" replied the bum.

"Okay", says the bus conductor. "You didn't hear this from me, but if you go to the graveyard on Wednesday at midnight, you'll see her by one of the graves praying for the Holy Ghost." The bum thanks the conductor and anxiously waits for Wednesday night. During that time, he finds a discarded white sheet and cuts two holes in it. On Wednesday at midnight, he walks into the graveyard and sure enough, there's the nun praying at a grave for the Holy Ghost.

"WOOOOOO!", cried the bum, trying to be as ghostlike as he can. "I am the Holy Ghost and I want my way with you!"

The nun looks up and is disappointed. "Oh. There you are. Well, trust you to appear at the wrong time of the month. You'll have to take me fom behind."

So as you can all imagine, a lot of in, a lot of out, and even more shaking it all about ensues. Afterwards the bum throws off the sheet and shouts "HA HA! I'm the bum on the bus!"

The nun throws off her habit and shouts "HA HA! I'm the fucking bus conductor!"