For the past several years (probably about two to be more exact), my sister and I have had this game that we play. It all started one night when the two of us were home alone.
My sister, who is two years younger than me (so 14 at the time) was in the shower when I started to get really horny. I had always been a secret exhibitionist, going around the house naked when I was home alone and stuff like that. So I decided it would be fun to stand outside of the bathroom door and listen to her shower while I jerked off. So walked up to the door, unzipped my pants, and pulled my hardening cock out. I started jerking off and really got into it. By the time I realized the water had turned off, it was too late. Just as I was about to cum, my sister opened the door to me jacking off. She quickly closed the door, and I shot my load all over the closing door. I came so much! The door was soaked and so was I. I really needed to use the bathroom to wash up.
I knocked on the door and apologized and said that I really needed to clean up in the bathroom. My sister opened the door and looked down at my dripping cock which was now pretty much soft, and she invited me in. She was still wearing just a towel, and I could tell her nipples were swollen. I started to wash my cummy hands, and grabbed some toilet paper so that I could clean up the door. While I did all of this, my sister still watched my cock which was starting to fill up again. I hadn't put it back into my pants so as to not soil them with the cum. When I was done cleaning the door, my sister asked: 'Are you gonna wash it now?' (pointing at my dick which was now semi-erect).
'Yeah,' I replied.
'Can I help?'
That line shocked me. She had been so timid to this point and then she just asked to help me wash my cock! After a moment of thought I said: 'Yeah...okay I guess.' Her face lit up like a Christmas tree. I had to take a shower anyway so I figured I just clean up in the shower. I started to get undressed and gave my slippery, cummy cock a couple of rubs. Before I got into the shower, I looked at myself in the mirror. My cock was really shiny with all the cum. As I got in, I continued to rub it because it really needed the attention. I then invited my sis to join me. She immediately dropped her towel, exposing everything. She had very nice tits for a 14 year old, but what really got me was her pussy. I had seen tits, but never a pussy. It was a beautiful sight. So beautiful in fact that I came instantly (combo. of rubbing and visual effect). The cum flew at her, some landing just above her pussy. After a little awkward silence, I turned on the water and brought her close to me so that we could close the shower door.
I immediately started feeling her up, but she wouldn't have any of it. She just wanted to feel my cock which I was plenty happy to let her do. She definitely wasn't a pro at handjobs, but she was good enought to make me cum again! This time the cum was knocked down by the water stream and when directly down the drain. I let her wash the rest of me and then we left silently, without talking about it until the next day.
The next evening we were home alone again...And she was in the shower again. I figured I'd do the same thing as last night. So I stood outside the bathroom, this time completely naked, and jacked off. This time I finished before she did. I left her a nice puddle of cum on the ground in front of the door. When she got out of the shower she yelled: 'Fred! I stepped in your cum! Are you gonna make this a daily thing.'
Well, I did make it a daily thing. Everytime she finished her shower before I came, she would finish me off in the shower. Everytime I came first, she would just find a present. We stopped about a month ago, just after I turned 18. I never got to masturbate her, and she never did anything more than a handjob.