A blonde buys a used sports car. However, during the first joy ride, the engine jerks and the car slows to a stop. The blonde calls a tow truck. The mechanic sets to work, and 10 minutes later, the car is running again.
"What was the matter?" she asks.
"Simple really, just sh*t in the carburetor" he replies.
Taken aback she asks, "Oh, how many times a week do I have to put that in?"