I never expected this to happen, but I won't forget it, either!
I was laying on my bed, with my girlfriend beside me. We were making out, and she suddenly grabbed the lube and told me to take off my pants. I have around a 6' dick, with a very light amount of hair (I like to wax it).
She started jacking me off. I made a lot of precum, and my balls were noisily slapping against my body. I started moaning really hard, and the head of my dick was turning purple because of how good it felt and how much precum I was making. Since she knows how I like it, she would stroke it slow, then when I got harder she would start stroking it faster and faster. It was feeling really good, when a friend of mine called. She answered the phone, but she kept on jacking my cock.
Knowing that she was talking to my friend and that I could be caught having an orgasm nearly sent me over the edge. My girlfriend said she only intended to tease me, and never meant me to cum, but it was too exciting. All of the sudden, a huge load of cum shot out of the end of my cock, sprayed on to the bed, and on to my pubes and happy trail. Some even sprayed on my arm and onto the other side of the bed! Sometime during this, my girlfriend said, 'Hey, can I call you back?' and hung the phone up really fast. We pretended that I had burned myself with hot water from the sink. Hahaha!
It was the strongest orgasm I've ever had in my life. I hope it happens again.
Writing this has made me hard, so I'm off to stroke myself to the memory. Happy jacking.