Boner Problem...

I am attracted to this guy I work with and the feeling seems to be mutual, although neither of us has acted on it. The problem is, just being near him gives me a chub. And, if we lock eyes I get an instant boner. Does anyone else have this issue? How can I flirt without getting turned on at the same time? Every time I see/talk to this guy, I now have to avert my gaze (look down or in the other direction) for fear that if I make eye contact for even the briefest moment, I'll get a boner...