Grandma doesn't always know best.
 

He'd been playing outside with the other kids for a while when he
came into the house and asked her, 'Grandma, what's that thing
called when two people sleep in the same room and one is on top of the
other?'

She was a little taken back, but she decided to just tell him the
truth. 'It's called sexual intercourse, darling'

Little Tony just said, 'Oh, OK,' and went back outside to play with
the other kids.

A few minutes later he came back in and said angrily, 'Grandma, it
isn't called sexual intercourse. It's called Bunk Beds. And Jimmy's mom
wants to talk to you.'