Okay, let me lay this situation out for all of you:
At some point next year, I'll be moving in with a friend. This friend, who I used to know as Eric, is a Transsexual named Laura. She hasn't been happier. Now, I've loved to crossdress for year, but I was caught by an older sister and was forced to endure some public embarassment. I was known as Sarah for a while, among other things. Now, I have moved and am back to what I used to do- crossdress when I feel like, but aside from that, everything is "normal".
Now, a few nights ago, Laura asked me a huge favor. Basically, she'd like a sister while she goes through HRT and surgery, and since I'm the only one she knows who would be okay with it....you get the picture.
As long as she was nice, I decided I'd be as well. So, I decided, while I'm at her house and until she can get her life in order, I'll be her younger sister. No harm for me, as long as it is all reasonable.
Now, because she has a habit of being depressed, I decided I'd let her have some fun. I decided to let her make up Sarah; her personality, how she dresses, etc. She did so, and Sarah is pretty conservative and not hard to pull off. However, the one stickler is that Laura wants me to be Sarah at all times. I don't really care, except I'm worried I won't pass. So, I've come here for advice.
I understand that at first glance, this may seem easy, trivial, etc. However, the important thing to note is that this may be for years. As such, I need good, strong advice. Before that advice is given, however, I'd expect there to be some questions regarding me and whatnot. Fire away.
