A guy has been asking the prettiest girl in town for a date and finally she agrees to go out with him. 
He takes her to a nice restaurant and buys her a fancy dinner with expensive wine.
On the way home, he pulls over to the side of the road in a secluded spot. 

They start necking and he's getting pretty excited. 
He starts to reach under her skirt and she stops him, saying she's a virgin and wants to stay that way.
"Well, okay," he says, "how about a blow job?"
"Yuck!" she screams. "I'm not putting that thing in my mouth!"
He says, "Well, then, how about a hand job?"
I've never done that," she says. "What do I have to do?"

"Well," he answers, "remember when you were a kid and you used to shake up a Coke bottle and spray your brother with it?"
She nods. "Well, it's just like that."

He pulls it out and she grabs hold of it and starts shaking it. 
A few seconds later, his head flops back on the headrest, his eyes close, 
snot starts to run out of his nose, wax blows out of his ear and he screams out in pain.

"What's wrong?!!" she cries out.
"Take your thumb off the end!!"