I could feel his cock throbbing inside me, and I knew he was close."Fill me with your cum," I again begged of him."You'd like that wouldn't you slut,"...he said back.I loved it. My asshole was a slut for his cock. He kept thrusting hard inside me. I moaned in pleasure, as his cock stiffened and he fucked me one last time, pushing his cock as deep into my ass as he could. His cock throbbed, as I felt his warm semen shoot out inside me, in multiple spurts. The feeling of my cum and cock filled. “You better be careful Sis, you’re easy prey for the beast in my pants dressed like that.”She paused with the lace lingerie’ half way up her legs and looked at me “Not now, you have to take pictures.”‘Not now’ – A surge of anticipation swelled me until my pants were too tight. When Shelby finished putting on the bra and panties she raised her arms over her head and posed “What do you think?” Shelby was 28 years old but neither advancing age nor gravity had begun to define her body. My sister. I called a cab to go to the doctor (Yes, it was that bad).When the cab arrived, the driver said, "Hey hey, wait! You are peeling like crazy! You are not getting in here without something to cover yourself!"I went inside and bundled myself in a blanket (It was 64 the next day). I went inside the office and waited for my appointment.The doctor took one look at me and said, "GOOD GOD MICHAEL! WHAT DID YOU DO?!" I told him about the water park. He said there was only one medication that could stop. I spanked her tits with my dick too. I reached behind and again, ran my fingers over her wet pussy, never allowing them to dip inside her. She was soaking wet. I was rock hard. It was time to take this to the next level. I untied her feet and pushed her knees to her chest. Her hairless pussy was glistening with her juices. I thrust my finger deep into her tight asshole. This caused her to twitch and grunt. I fucked her ass with my finger until I thought she was going to pass out. I sat up.