I have a (married) buddy about 2.5x my age who casually mentions that he sleeps in the nude and frequently asks me to go hunting with him. Keeps saying I'll get all "chubbed up" when I shoot my first buck. Makes cracks about having "sweet cheeks" and having to be careful not to be mounted during the rut. We talk pretty intimately--but never expressly--about the size of certain body members and / or sexual escapades.
If he weren't married, I'd totally make a pass. Since he is, though, as far as I'm concerned he's just a friend who's in touch with his feelings and who appreciates an attentive ear when the topic of hunting comes up.
As for your curious hetero, I find that men respond well to frankness. Laying it on the table works pretty well for me. I own it, instead of putting it on them. "I'm getting mixed signals. From someone in my situation, some of what you're saying can have another meaning. I don't walk this road too often, and I don't care to learn the ropes right now through a very tedious and drawn-out charade; I'd rather cut it to the quick and leave zero ambiguity as to my boundaries." Dumb down language as appropriate.
I usually just set the limit
carte-blanche: my cock / ass is off limits, because straights and their burgeoning curiosity aren't my cup of tea. I'm already past that phase of self-exploration. I don't want to take X number of steps backward for the sake of someone who, in the end, probably has little to offer to my character development. Get to a point where you're comfortable in your own skin, okay being straight and dabbling in the cock from time to time. I know I'm a fine piece of ass--I don't think anyone would hold your fling with me against you. Well, I mean, except that it's a trophy you have--and they don't!
If you're interested in that cock, though, instead of giving him an excuse, or cutting off his tentative fingers (or cock!

) ask him point blank if that's what he's after (right now). The right now can help sometimes--he isn't
always a fag, after all.

Well, might not really be a fag at all, but that's neither here nor there.
Please pardon my use of such a derogatory word. I've been watching a lot of French films lately. I'm kind of inured.
