A pillow placed between two men sharing the same bed, to clearly define the space of each and prevent unintended / unwanted homosexual encounters during the night. Poss. homophobic.
ADAM: I don't want to sleep on the floor. Can't I sleep in the double bed with you tonight?
STEVE: I feel uneasy about that. I miss my girlfriend and might roll over and hold you in the night.
ADAM: Don't worry, we'll put up a gay-barrier!