A form of gaydar most commonly, but not always found in persons with ambiguous sexuality or faghags. It does have glitches and occassionaly fails, specifically with short-term scans such as 'first glance'. It's two main functions include a shock absorber for when someone comes out of the closet and finding potential hook-ups for one's gay counterpart.
My coming out doesn't surprise you?
No, my gaydar BETA picked up on that years ago.