Hi all,
I'm new to this forum and would appreciate some feedback regarding a sexual fantasy I replay in my mind every time I masturbate, that I'm very uncomfortable with.
I'm an 18 year old virgin male. I have been with girls but before only ever kissed them.I have a very high sex drive and I am very curious and nervous about having sex.
Masturbation for now gets me off until the proper time comes along.

I guess I masturbate about twice or tree times a week. Up until a few months ago I used to jerk off to regular porn on the internet. That all changed the day I saw my older sister in a pair of very sexy panties. My sister Sarah is 4 years older than me and she now lives away from home and only calls around at weekends.

It happened a few months ago when myself and Sarah were at home alone one Saturday evening. Sarah was going out that evening and in a hurry getting ready. I was watching TV in the Den room not passing any remarks on her at all. All of a sudden she comes into the room wearing a tee shirt and panties. She came in looking for the clothes iron and started to look around the different presses in the room. The tee shirt was long enough to cover her panties but as she moved around the room and looked up in tall presses I could see her sexy panties in full view for most of the time. She was in a hurry and I dont think she realized I could see as much as I did. I was immediately turned on. Sarah is tall and slim. A lot of my friends think she is hot.
Up until this moment I never thought of her in any other way other than she is my sister. Never before did I think of her sexually. Now I cant get the image of her in sexy panties out of my head.
A half hour later she went out for the night and I was home alone. I was still very sexually charged. As soon as she went out I went into her bedroom and opened up her panties drawer. This was the first time I ever did this in all my years growing up. I could not believe all the sexy panties she kept. I had such a huge urge to try on her panties and masturbate. and I did. The orgasm was so much better than the regular porn orgasms I have. Afterwards I felt guilty and dirty. She was my sister after all. It was very strange because II have no incestuous feelings for Sarah.
It was all about her sexy panties.
This now continued every time I had the desire to masturbate. When ever the house is empty (not very often) and I get the chance i will try on her panties and masturbate. I am always careful and I never cum on her stuff. When I cant jerk off with her panties I find myself imagining Sarah wearing her sexy lingerie. I imagine her getting dressed and walking around in her bedroom in her underwear. I also imagine her reaction if I walk in on her by accident. How would she react to me seeing her in her sexy lingerie?

Its like I cant think of anyone else now when I masturbate. I feel so bad for going through her stuff for one and also that she is in my mind when I jerk off. Surely this is not normal?
I would be so embarrassed if she or anyone else ever knew. The thoughts of having sex with my sister makes me feel gross.

In the last few weeks while jerking off I now have a fantasy where Sarah catches me stealing her panties and as a result locks me in one of the storage cells in our basement as punishment.
In this fantasy she makes me wear her panties as she locks me in the cage and warns me not to jerk off. In my fantasy she tells me that if I jerk off in her panties she will leave me locked in the basement cage for 24 hours. If I dont jerk off she will let me out in two hours. I always fail and end up jerking off in her panties right in front of her. I can vividly picture her looking at me in disgust as I masturbate in front of her. She then leaves me overnight as her prisoner.
I have never experienced orgasms like the ones when I'm wearing her panties for real and imagining her looking at me in disgust through cage bars. Porn was never this good.

So, am I normal? Do guys my age have ****ed up fantasy's about masturbating in their older sisters panties while being locked up as her prisoner?
I feel its having an effect on me as I feel dirty and awkward when I'm around her for real. She has no idea what goes on in my head and I think I a little screwed up because of this.
I wish I never saw her in her panties that Saturday night. I didn't come looking for this.

Am I a freak?

Stefen