Uncle is beeing a fucking perv

My sister Molly and I finally had the house all to ourselves. Our parents went to party 2 hours away I knew they'd be gone all night. We hadn't been able to mess around all week, and we were both really horny. We started making out and got naked, then I started plowing Molly like crazy. MY SISTER IS SO FUCKING HOT!!! It was awesome then all of a sudden Molly screamed. Our creepy Uncle Lew was sitting on the sofa next to us touching his dick. I told him to get the fuck out. My parents don't ever invite him over because he's such a weirdo. He told me to calm down and showed me his phone. He took a bunch of pictures of me and Molly having sex. Uncle Lew said he was just here to babysit us, and if we didn't want our Dad to see those pictures we'd better do just as he said. I called him a fucking creep, but he just said he wanted to help out. He told us to keep fucking and he would assist where he saw fit. We didn't know what else to do, so Molly and I started having sex again. Uncle Lew is such a fucking perv, he kept touching Molly's hair and rubbing her boobs while we had sex. And he was saying all this creepy s#*t the whole time. I couldn't believe what was happening. Uncle Lew told us how good of a job we were doing and how much he loved us. I wanted to beat his ass so bad, but I couldn't risk my parents finding out how close Molly and I have become. Finally he told me to cum on my sister's face. Then he said he had a special treat for Molly and told her to lift up her feet. Uncle Lew came all over Molly's feet and before he left, he told us he'd be checking up on us again very soon. I think it's time to change the locks...