Being queer myself, I'm not sure how I'm perceived by straight men. However, gay men don't always pick up on my queerness. Then again, unless gay men are congregating together in community, where they know they can act and talk queerishly and where such stereotypical quirks are expected, it's often difficult to make assumptions about any man's sexual orientation.
Might as well get it out in the open, though, and make it clear from the get go. You're out at a bar meeting other men. It's only natural that some of those guys will want to know.
I do find it amusing that straight men automatically assume that, if another guy is gay, that he's attracted to them and wants to get it on. Then again, a lot of straight men make that same assumption of any woman who engages in conversation in a bar. Let's face it, a whole lot of men are simply emotionally, socially, and sexually immature.