Someone who is said to hide under desks, in the workplace, whilst people are working, in order to look up women's skirts.
"LLOYD YOU DESK RABBIT! GET OUT FROM UNDER MY DESK!"
Someone who hides under an office desk with out informing the desk's owner that they are there. Being a desk rabbit can have many benefits, one can listen into office gossip, find out who the boss is going to fire next or even look up the secretary's skirt.
Moss: Roy's stuck underneath a lady's desk.
Jen: What, still?
Moss: Look, I know that normally this would be very funny but he's been under there too long for a reasonable explanation. If that woman looks down shes going to assume he's a desk rabbit.