The 18-year old girl comes up to her dad. "Daddy, the prom's tonight, and I promised my date I'd pick him up. Is it okay if I borrow the car tonight?"
Her father thinks, and says, "Okay, but only if you suck my dick."
Naturally, she is shocked, but her father's mind is made up. She really wants the car. So, resigned to her fate, she get down on her knees and starts doing the deed. But after about 2 seconds, she looks up in disgust, and says, "Daddy, your dick tastes like shit!"
"Oh yeah, that reminds me," her father replies, "you can't have the car tonight; your brother's borrowing it."