I was watching my niece one night when my brother needed a sitter on short notice. Usually he wouldn't ask me but I was sort of like a last resort to them. I agreed to watch her. When they dropped her off I didn't know it would be for all night. I saw them walking up with her back pack. I thought it would only be for a few hours but turns out it was an over night thing. So I brought her up stairs and let her watch her cartoons. Night time came so I made her a bed on the floor. We both went to bed as we were still were watching TV. The movie was almost over and my niece was almost asleep. But as she almost fell asleep she was uncomfortable on the floor. And asked to sleep beside me. I said "are you sure you don't want an extra blanket or some thing? My bed is small and you won't have much room?" She laid beside me and said "it's OK" so as she made herself comfortable snuggling up next to me she wrapped her legs around mine and held her hand on my stomach. And said "night uncle" I said "good night sweetie". She stayed beside me but kept moving around. Her knee kept rubbing against my dick and it started getting hard. I asked her to stay still and she said OK. But her knee was still on my dick so it started to get hard. She realized what was happening and giggles a bit and smiled as she looked up at me. She looked down and slowly moved her hand down my shorts. I didn't know what to say or do so I just let it happen. She grabbed my dick and it started getting harder. As she stroked I grew in her hand which seemed to turn her on. A few more strokes and she had me in her mouth. I was loving every second of it. She obviously knew how to sick a dick. After a few minutes she stopped suckling and looked up at me. She said "can we fuck" I said " I don't know baby girl, did you bring protection?" She said yeah it's I'm my bag. I took it from my dad before I left. I knew I was sleeping over." So she got up to grab it then I put it on. As she got on top of me she sat down slowly on my dick. And smiled as I was all the way inside her. The first few pumps were slow. But as she eased into it she started riding me faster. After a couple minutes of riding me she was getting louder. It was really turning me on staring at her little tits bounce around on top of me. We fucked for about 20 minutes. I ate her out and she sucked my dick. We both fell asleep together then wen the morning hit. She woke me up with a blow job, and morning sex. I didn't relive my niece was a little slut but damn can she really ride me. Her dad came to pick her up and before she left she wispered in my ear, "let's fuck again soon uncle" then grabbed my hand and put it on her ass. I was worried her dad saw but he was always busy on his phone so didn't notice. She ran back to the car and they drove off. The next few weeks went buy and all she did was ask to visit me. So they let her spend the weekend at my place. We fucked all over the house. She really is wild.