It entirely depends on the person and your comfort with them. I think relationships that start prior to or during transition have a different dichotomy than ones that start after, too. My ex, I really don't mind using my parts. With newer people... I don't even know, really. Honestly, I've sort of avoided that topic with recent partners because they don't know what to do with it, I don't know what to do with it, and talking about it sort of ruins the mood. Nothing seems to excite me anyway. All I get out of physical contact lately the pleasant tactile sensation of being caressed or massaged. No sexual arousal.
The last girl I was with was sort of FTM. He, she, argh I hate dealing with pronouns regarding that person. He goes by a male name and asks for it to be used most of the time, but switches between girl and boy pretty often and has admitted to other people I know that he's afraid of surgery and drugs. When we went to bed, he kept his boxers on but didn't seem to mind the top stuff.
Of course, he wouldn't communicate to me what he liked and I couldn't find it, and he didn't want to bother with the stuff I enjoy. After he didn't have much success with me either, he said, "God, you're such a girl. Girls are complicated. I'm lazy." And bitched that I was way more of a woman than the other MTFs he knows.
I asked him what he expected, because I told him about my complications. And I asked if he'd ever had much success touching a woman before

He's pretty much a gay dude as far as we can tell. And 18. God, teenagers are just not worth sleeping with.
Oh god I just realized I had an awkward trans on trans encounter.
But versus say, my ex, who is the only person I'm actually sexually attracted to (and believe me, I've been trying since we broke up), which is probably because we started back prior to my transition, where I am comfortable with my body with her. She spent so much time, sometimes literally holding my hand while I learned to be more comfortable with myself and to just enjoy what was going on.
I personally don't enjoy receiving oral (except from her), but I do love physical contact. Skin to skin, body to body, where you just sort of meld together, and you don't think about who has what parts - that's why I've been able to enjoy sex well enough. Though I still can't shake the 'duty' and 'obligation' feelings when I'm on top of a girl, because the whole 'will you satisfy her enough before you finish?' thing is a big stress for me, even though it's usually never a problem.
I think the real problem I've discovered is that I need a real connection to a person to be satisfied, and that isn't something that really comes along that often. So I'm trying desperately to find something that hits and sticks, but ultimately, I'm just flittering through casual experiences that are teaching me the things I'm ambivalent about.
I may also have just reached the point where I just can't focus on sex prior to SRS.