This happened when I was 20! I was out shopping on a quiet Tuesday afternoon in my local town. I picked some clothes and went to try them on. I headed towards the male changing room to find they were closed as they were having a change around in store. The girl on the shop floor shown me to the women's where one side was been used as the men's. I went in to the changing room and went about trying on the clothes I had picked. As I was undressing I heard a woman been shown to her changing room. I thought nothing of it and carried on. I put on some clothes and wanted to check them out in the full length mirror outside the cubicle. As I drew my curtain and stepped outside I noticed that the woman in the cubicle hadn't closed her curtain all the way. She had her back to me but hadn't noticed me with the help of the mirror on the wall in front of her I could see quite a bit. She was about 5,5 tall a size 10 curvy carried a few extra pounds but in the right places dark hair late 30s I guess. I don't know why but I decided to step back inside my cubicle leaving the curtain open a bit a good six inch gap. I watched as she stripped down to a bra and thong with her back to me unaware. Her bum looked amazing and my cock was soon growing. My heart was racing and as quiet as I could I decided to strip naked my 7" cock now bobbing up an down. I've pretended to hang up my clothes hoping that she would turn round and see me. I didn't look across for about minute but when I did I got a shock she was standing there curtain drawn halfway in her underwear looking at me with a little smile on her face. Unsure what to do I just apologised she said very nice. Feeling a little shy as I have never done anything like this before I couldn't help but look her up and down. As we just looked at each other all of a sudden I could feel my cock twitch and tighten and suddenly cum just began to run out of my tip landing on the floor in front of me. I hadn't even touched my cock she looked open mouthed as I came before having a little chuckle. Naughty boy she said before turning round to continue trying her clothes on. This was my first ever premature experience thinking back I think it was the excitement as well as the fact I hadn't wanked for a a couple of days before this so my young balls were full. Has anyone else here ever came without touching.