You would play a man who isn't very nice and who is involved in illegal activities. I would play a nice young man (the younger the better, for reasons you'll see in a moment, but old enough to stay within the rules) whom your character dominates and feminizes.
The background (not necessarily to be played out) - Mom had a talent for always picking assholes - guys who would say a couple of nice things to her to get her into bed, then slap her around, take all her cash and food stamps, use her car without asking, etc etc. But your character took it up a notch. Your guy is a small time drug dealer, and doesn't like the fact mom is using shit he could be selling. Once when he was slapping her around she said something about her son (my character) saving her.. so he drags the boy from the crappy little bedroom where he was cowering and forces the young man to give him a blowjob in front of mom, completely breaking both their spirits (as if they had any spirit to begin with.)
Finally, he had enough of this bitch and decides to leave, probably while she's lying on the living room floor of the shitty little trailer house, all strung out and barely conscious of what's happening. He takes everything of value -- to include her car. And her son. The boy will be his virtual slave, and he tells the woman if she tries to report him for stealing the car, etc, he will hurt the boy. Though he prefers women, he forces the young man to perform sexual favors on him when he can't find a woman to do it.
Their destination is south ... toward the Mexican border - a source of drugs for resale in the U.S. (The nature of the criminal activity is open for discussion if you have other ideas ... smuggling ivory, rare species of fish or fowl, etc) And the guy has an idea. The young man with him is smallish and effeminate looking, and would make a pretty girl. He decides this will be useful, as many people they encounter along the way will be more receptive and willing to help a pretty young girl than two guys.
So my proposal is we start with my character, newly feminized and terrified, having to use "her" femininity to help them along. They have an old unreliable car, no money, etc, so my character had better come through or else.
My idea is that my character becomes a manipulative tease in order to get things for their survival - food, gas, etc - and probably even starts falling for your character even though he treats "her" like crap.
Willing to play in the forums or via IM. Please let me know (respond here or PM) if you're interested, and thank you for your time.