What bulb is in that socket, if it is an 1156 and you have to keep pushing it back in then you have one of two common problems.
Problem one: Failure to turn the bulb to lock it in, It turns clockwise, just a couple of degrees, so the pegs on the base engage latches in the socket.
Problem 2: Center insulator cracked and not holding the center pin against the lamp properly.
Single contact center insulators are hen's teeth, I looked all over for 'em and finally stopped in a Pilot or Flying J east of Indy last spring,, he had 'em on the close out shelf, but ask at your local Audo parts place, they can order them if they don't have 'me in stock.
Home is where I park it!