That means that the boy really likes her.
Matters if you have close on or not. If not then he wants to get dirty.
it means he likes you but he does not want anyone to know
He's probably just playing with you
He probably likes you
he's a horny pervert who can only think about getting into your pants;)
... Maybe
he likes you
they like you
You got stuff in your teeth
It means you're still in middle school.
He is probably just messing with you. Seeing if he can get a rise out of you.