I'm dating a transgendered girl (sex question)

[benwest]

Hi,
I'm new to the forum and am here to seek advice. I'm currently dating a beautiful girl. We met at work. I never knew she was transgendered until our second date when she told me. She's very feminine and is pre-op. I had never even thought that I would ever date a transgendered person, however she is beautiful, sweet and my heart beats faster whenever I'm with her. I really think I'm falling for her.
We have dated for four months. We only got sexually active in the last two weeks. Not because I'm not turned on by her but she wanted to take it slow. So far she has performed oral sex on me twice. I got her top off the last time but she kept her jeans on. I would like to go further and am a bit worried about it.
I know where I can stick it but how should I treat her penis? She never mentioned any preference and I'm afraid to ask. Should I ignore it or play with it? I'm not even sure how I would react. I have never even seen a real erect penis other than mine. However I have been browsing for transgendered pictures and have found them quite arousing.
Thanks for any advice. I know this is probably a dumb posting but I really like her and would like her to have a great time the first time we make love. Right now I feel like a heel as I got the two best blowjobs of my life from her but did not do anything for her at all.