Definitions by Paul Barry Knowles

behind the door 

someone is "behind the door" when they only have a simple understanding of a situation, a person is ignorant or oblivious to the full meaning of a situation or is naive. Often used when talking about sexual meanings or situations.

"I don't think he understands"
"Yeh, he's a bit behind the door"

behind the door by Paul Barry Knowles May 28, 2008