Person B: You showed up on my gaydar.
It's like Spiderman and his Spider sense. He can just "feel" when there is danger nearby. Gaydar allows you to "feel" when there is gayness nearby.
Usually the gay/bi ones are always the good looking ones. ie: Nick Lachey, David Beckham, Channing Tatum, Ryan Carnes, Chad Michael Murray
and usually the ugly one's are hetero.
ie: Dick Chaney, George Bush and Bill O Reily (sad isn't it)
Jeff: Dave? he's gay, my gaydar pinged when i saw him
Kate: ohh thats too bad. who else is gay?
Jeff: Your husband
Kate: Noooo you lie you fag!
Jeff: I slept with him so take that you fat bitch!