One day no one was home. We have a completely secluded backyard so I went skinny dipping (as in naked) when my little sister came home, which I didn’t know. She must have seen me and decided to go swimming, too, but she didn’t know I was naked; at least I don’t think she did. She ran out in her one-piece swimming suit and jumped right in (my little sister is 10) so I tried to act casual and we were in there for a solid half hour before she asked if we should get out I told her she could out I would stay in for a little longer. She said “okay” and proceeded out of the water, grabbed my towel and started to dry herself off then she wrapped it around her waist pulled up a chair and sat down to wait for me. I started to get really nervous. I just stayed in there for another 20 minutes in the deep end hoping she wouldn’t see, when out of no where she said, “Michael, whose bathing suit are you wearing?” Apparently mine was on the drying rack and I only have one pair (I’m the only guy that lives in this house so I couldn’t say it was my dad’s or brother’s and I only have one pair). “Part of mom’s 2-piece,” I said really embarrassed, even if it was a lie. She burst out laughing and told me to get out so she could see. I told her no and she said she would call mom if I didn’t, so I had to tell her the truth. “I’m not wearing one,” I said. She laughed at this but not as much more of a giggle and told me to come out or she would call mom and tell her I’m skinny dipping (my mom threatened to ground me for a month and give me a spanking last time she caught me skinny dipping; that’s the only reason I complied but I don’t think she knew I’ve been skinny dipping before). I walked out, hands covering myself, and she just giggled some more and told me to raise my hands while she dried me off with the towel. I slowly complied and at first she moved up my legs then on my upper body arms then back down, only this time drying my private areas which she kept laughing because my penis was small (the water was cold). She grabbed my hand and took me inside to her room and told me to lie on down on my back on her bed while she got something. I did with my hands on my crotch as a cover. When she came back she had a diaper and supplies (apparently she loves diapers on me and this is because of your site she is actually making me write this right now. I’ve been diapered 3 times since the incident and it never stops being embarrassing.) “What are those?” I said shyly. “Your new outfit for the next ten minutes, or I call mom.” She told me to put my hands to my sides. When I did she pulled both my legs together and lifted my lower half up a little and slid a diaper underneath. Then she let my legs back down spread them and began applying ointment or oil or something. It felt so good, I’ll admit to that, and I immediately asked if she had ever diapered someone before. “The neighbors little boy, but he wasn’t as excited as you,” she said, giggling at my now fully erect penis. “I take back the small comments.” She grabbed a wipey and with it in hand, grabbed my penis and began rubbing hard and fast. She stopped right before I reached the climax and removed her bathing suit (not much to see) I commented on the little bit of pubic hair she had and she blushed, which turned me on somehow knowing that embarrassed her (I have no pubic hair now, my sister shaved it off). She continued to grab hard and fast (this is really embarrassing, getting your first hand job from your little sister). After only a minute I exploded she laughed, finished cleaning me up and finished putting the diaper on. Then she called her best friend who is 13, so I’ve seen her around my school. It was really embarrassing and she made me pee the diaper; then they both re-diapered me. That’s when I lost all my pubic hair. Neither of them have told anyone of this incident but they say they will if I don’t do everything they say (as I write this I am naked and 4 girls watch me, not the screen, though my little sister says she will tell them why if I didn’t do this but now I am allowed to get dressed.)