I have a different angle on it.
I think more about affection, caring and love. I also think less about man, woman, TS, whatever. Maybe without even labels.
I think it might be from being an "old fart" and having values change, but I am thinking more about the person that exists inside of the skin. I think if I care about someone deeply, feeling what is going on inside of the person and there is a mutual desire to express that caring and affection physically, then I am not sure what I would do. It would be the person that I want to express my internal feelings for in a physically way, if they want to do the same.
Look, sometimes, conventionally going from male to female, there might be a situation of a woman having something physically unexpected, from scars to a mastectomy, etc. There was one woman that I cared about that had a terrible accident as a child and had burns all over her body, which you couldn't see until her clothing was off. It didn't change how I felt, if anything I felt more empathy and more loving and caring.
If there was a penis with a guy, or hopefully with a TS, or a post op, if I felt the desire to express my affection, caring and love that I am feeling inside, physically, then a big part of that for me, probably the biggest part, is the joy of pleasing the other person.
I have been married twice to woman and have three boys.
Jon