Alright, so I'm bisexual and FtM. I'm four and a half months on testosterone, and pretty much want to exclusively date guys. I get plenty of attention from bisexual and gay guys, and they're who I seek out. Occasionally, though, I'll have a straight male friend who's set off my "gaydar" really hard start offhandedly flirting with me and acting like it doesn't count because I don't have an actual penis. All of the gay guys I talk to recognize me as male, even if they personally wouldn't wanna date me because of my trans status- I pass fully as male, talk to friends as male, work as male, so on and so forth. Yet there's always that one "straight" dude who wants to act like it's totes cool because I'm not cis. The most frustrating one so far has been a bicurious guy I'm friends with who I'd talked about um.. getting together with.. a few times, but who always acted like it'd be exactly like being with a girl. Gay and bisexual guys never do this to me, it's always these in-denial straight guys. How do you tell them that it's not like that in a way that doesn't make you seem like a jerk?

I don't see how you are any obligation to be polite to someone who is basically telling you that being with you sexually would be the same as being with a girl. 

I don't avoid sounding like a jerk. I firmly state, "I'm a guy." If they push the issue, I repeat myself louder. It's blunt and kind of aggressive, but it gets the message across. If it doesn't I don't want to be around them anyway.

the best approach in situations like this is be direct and clear imo. YOU being comfortable and accepted as you are is what is important. if someone can't accept that, do they really deserve to be with you in any way? if they can't respect who you are, your identity? what happens when it comes to boundaries? using words you might not like? if they don't understand that it might just be one dysphoric and unpleasant experience for you.

I agree, just be direct about it. If they want to do something with you sexually that you aren't comfortable with, just tell them that's something you don't enjoy and you feel it wouldn't be congruent with how you feel about yourself.

Oh, I just act like a jerk. If the guy is straight I'll put emphasis on him being attracted to men. If he's bicurious I'll point out how I'm not into being people's experiment but there are lots of gay and bi guys who do. Or I'll point out how I'm not discreet and have no intentions of being that way.

"We'll make a cute little couple when I grow a beard a few months." (Mind you I doubt you'd grow a beard in a couple months, but I've used this sort of response to good effect when a guy didn't see the point of gendering me correctly. I said "You are going to look really stupid when I come in her with a full beard."

--Jay

haha. oh the things i'd say if this happened to me. however i'll save my vulgarity; if you really want to avoid being a jerk, don't speak to them about dating or terminate the friendship. if you've the patience for it, you can try to politely explain how being trans works, but i've noticed people of this sort don't listen unless you give it to them straight (no pun intended).

Tell them you're a top? lol
No, I think it's really just a way for them to not feel emasculated by being attracted to a man.

I am on the mtf spectrum, and I have a gay guy that has tried a few times to hook up with me and I told him that im not intresested because I am a women and you are into men, and it makes me uncormfortable that you are interested in me. hes backed off since!
You definitely need to confront him though!

Direct and clear is the way to go as someone else stated. I've been in your shoes before a few times and one time I got rid of the interest by telling him he'd look great bending over,  if you catch my drift.    Straight guys don't like being told that apparently.