Grandpa

There was a family gathering, with all generations around the table.

The mischievous teenagers put a Viagra tablet into Grandpa’s drink, and after a while, Grandpa excused himself because he had to go to the bathroom.

When he returned, however, his trousers are wet all over.

“What happened to you Grandpa?” asked his concerned children.

“Well”, he answered, “I don't really know. I had to go to the bathroom. So I took it out and started to piss, but then I saw that it couldn’t be mine... so I put it back!”