I went round to our friends house to use their pool whilst they weren't there. I went through the gate in to the back garden. I looked thru the bedroom window and in a dressing mirror saw the man masturbating. I crouched down and watched the reflection. I had never seen a penis before. He pumped it for a while and then would stop and gently stroke. Eventually he groaned and the cum shot over his stomach. He cleaned himself up.
I disappeared around the corner, waited a couple of minutes and then banged the gate. He came out to see who it was and after saying hello I got in the pool and he left the house. I had never really masturbated before but had touched myself but it was sometimes slightly painful. Being quite excited by what I had seen I crouched at the side and let the water jet hit betweeen my legs. I felt lightheaded and after a few minutes I guess I had my first orgasm. It was unbelieveable but I have not yet repeated it despite a number of attempts. All in all it was a great first sexual experience and I really enjoyed watching our friend.