Do you know other gays in your workplace? 1 in 10, right? This sounds like that episode of Friends where Chandler was trying to fix up a coworker with Rachel, but the coworker was gay, and everybody thought Chandler was gay, but they also thought the coworker was out of Chandler's league. It sounds like your coworker is being somewhat friendly. It sounds like you are young and not that well acquainted with that many people at your workplace? Dating coworkers can be awkward; if things end badly, you still have to see each other. Altho that might not necessarily be the case here so much. Just ask him the secret gay password.