We did something like this, the night before a friend got married.
To keep him from waking up, we covered his face with a rag soaked
in ether or chloroform (I'm not sure). We proceeded to shave off
*half* his mustache.
His intended was slightly disturbed when she heard the news the next
morning, so she decided to get us back. While we were in the ceremony,
she had someone sew up the pants legs to our clothes.
We got the last laugh though. As the newlyweds were getting into
the car, we pulled up in a truck, kidnapped the groom, and drove away.
We took him a few miles out of town, stripped him, and hand-cuffed
him to a road sign. Taught her.