Quite simply, male bodies have prostates and there placement and nerve count lets them act in a manner similar to the fabled and mystical G-spot (though I believe GGs have us beat out in nerve count). As a recent development (probably around the last month or so) I have been exploring this.
I have experimented in the past but not like this. It is different than the more typical manner of stimulation, and the orgasm is very much different. There is a build up, a genesis and the experience itself is more drawn out.
Engaging in stimulation of this manner has shifted focus of how I think. Now I really have pretty much no interest in captioned images, stories, and things like that. When I am engaged in the act the focus is not on imagining myself as female, or imagining getting turned into a female, there is no visage of autogynophilia visible. I'll still look at porn stills to get myself fired up but now instead of wanting to be the woman I simply want to be in her situation. As I am going, I am either too focused on the actual sensations to bother fantasizing or I am doing so about being with a man/male. What it would be like to look up and see a built chest looming over me or what it would be like to feel his hands on me.
This new found pleasure does have a downside... I kind of get hopelessly horny randomly throughout the day. @_@
I am going to continue exploration this way, it helps my sense of well being. It is a self pleasure method that makes me feel good about myself, at peace.
But in order to do that I'm gonna have to get myself some kind of toys.