I was sixteen at the time and horny. My sister, who was a year and a half older than me, had this friend, Susan. She had just turned eighteen and had a body that was unbelievable. She and my sister had been friends from when they first met in ninth grade and they would sleep over at each other's home from time to time. My sister had invited Susan to stay over on a Friday night. My mom and sister had to be somewhere early in the morning and my dad had to work which left Susan and I alone in the house for the entire morning.
I walked into my sister's bedroom to say hello to Susan. She always wore loose fitting pyjama tops and no panties. She knew I liked to look at her and I knew that she liked me looking. I only had on my boxer briefs and she had seen me many times like this and we were both very comfortable around each other. We made idle chit chat as she was making the bed and she made sure she bent over facing away from me so her top rode up in the back and gave me a good look at her naked ass. She then turned round and bent over again pretending to smooth the bed spread. Her top fell away and I had full view of her tits. I knew she was doing this intentionally. She liked me looking at her. She had the nicest tits and the biggest nipples I have ever seen. When soft, her nipples were flat and about two inches round. When hard her nipples got really small but stuck out about an inch and curled up. I had seen them many times and loved looking at them.
By this time my cock was rock hard and I figured it was making quite a tent in the front of my boxers. Susan looked over at me and said, 'It looks like someone needs some attention.' I looked down and my cock was sticking straight out of my boxers about six inches. I blushed big time. This was the first time that Susan had ever seen my cock and I wanted it to be under different circumstances than this. I apologized as I was trying to tuck myself back into my shorts and Susan said, 'Please don't be sorry. Don't you know that makes a girl feel good that she affects a guy like that.' Never the less I was still embarrassed and excused myself and went to my room.
Once in my room I dropped my underwear, put some lube on my cock and started to jack-off. I had left my door partially open in the hope that Susan would come by my room. I only had a few minutes to wait and my dreams came true. I heard Susan's voice behind me say, 'God, that must feel good.' I spun around faking surprise and trying to cover myself up. I said, 'Susan, I'm sorry. I just couldn't help myself. You are so beautiful and sexy I just had to take care of myself.' She said, 'Don't you ever apologise for that. In fact, would you mind if I joined or helped you?' I told her I would love it if she did both.
She told me she had never seen a guy do himself before and she thought it was very exciting and asked me if I would please keep doing it. She came over and sat down on the bed beside me. She took off her top and was sitting beside me completely naked as I was. She asked me to stand up in front of her so she could see what I was doing up close. My cock was only inches from her beautiful tits as I stroked myself. She asked me to play with her tits. Her nipples were so hard. I rubbed my penis head on them and she moaned. My precum offered excellent lube. Her legs were spread wide and she was fingering herself like crazy.
Watching her do this and playing with her tits took me over the edge. I told her I was going to cum and it was going to be real messy. She said, 'I want you to cum on my tits.' Her wish was my command and I started cumming. The first squirt hit her chin. Three more after that were all over her tits. I leaned closer so the rest of it would run out all over her tits. She told me she had never done anything like that before and the feeling of having my stuff all over her was overwhelming. She said it felt so warm and scooped some of it up and tasted it. She tasted much more of it in the years that followed.
Susan is my wife now of almost twenty years and sucking her long nipples still gets me off.