"What did you do at school today?"

"We played soccer in PE."

 "Cool.  Did you lean anything?"

 "We played this game where were were supposed to be pirates and we were supposed to keep the treasure away from the other pirates.  We all had soccer balls and we had to use our feet to keep the treasure away from the other pirates who wanted to steal it."

 "That sounds fun."

 "It was!  Because the ball is your treasure.... wait, that doesn't sound right."

Nearly nine years old and totally understands double entendre.  My work here is done.