Sex with teacher

A first grader comes home and announces to his father that he had sex
with his teacher. 

Well, his father's chest just swells with pride and he says to his son,
"I was a freshman in college before I
had sex with my teacher. I'm proud of you son. You know that bicycle
that you've been wanting for so
long. I'm going to take you out and buy it for you today." 

His son says, "Well if it's all the same to you dad, I'd rather go
tomorrow. My butt's still sore."