Granted, most dudes can get a bit randy at the drop of a hat. So the answer is, obviously, don't drop your hat.
OK, Smack, I'll give you an example. Last weekend, I spent a couple of hours out on the lake with a guy I hadn't sailed with before. We had a good time, but all sailing-focused and totally nonflirtatious. Fine. Then the wind died down, so we were heading back to the harbor under sail, but pretty slowly so there was not much to do but sit and talk. Conversation, as I recall, was pretty random and totally innocuous - recent travel; annoying airline rules; the lake levels; and boat & trailer maintenance in the offseason. And then this:
Inland: So you only repack your trailer bearings once every 5 years or so?
Crew (suddenly giving me The Look): Can I kiss you right now?
I have to admit, it sounds hilarious, but this is about the fifth time this year something like this has happened to me, and it's getting really old. If anyone can explain to me where I dropped the hat, I'd be grateful.