Extremely camp music, and a reference to stereotypical gay men who work out and often listen to it whislt doing so.
"Ooh, Simon, in the navy is on, lets pump some iron"
"Oil me up Paul, it's gay buff hour!"
"This sexy foam party is fab!"
"But what we need Simon is some gay buff tunes"
"You're right on there Paul, Oil me up and i'll get that mix tape I made you"
When you sit down somewhere (usually in a movie theater) and purposely leave an extra seat between you and a person of the same sex so as not to appear gay.
Dude, leave me a gaybuffer! You are so close to me you're practically sucking my dick.
The unused urinal(s) between two males when the extra capacity could be used. Most men would rather wait for someone to finish then have their penis in glancing distance of another man to avoid any assumptions of homosexuality.
Male 1: Why don't you just use the urinal between them?
Male 2: I need my gay buffer, I don't want them to looking at my dick.
When two straight bro's are forced to sleep in the same bed on an overnight stay at a hotel; extra pillows are placed between them creating a gay buffer.