In the shadows was her older sister Ellen, already on her third cum from watching, thinking of what she should do to her little sister with the horny ...oyfriend. She knew what she wanted to do, she just wanted the right moment.Susie was so busy pumping his cock, feeding the steady stream onto her nipples and then into her mouth she did not hear Ellen come up behind her."What are you doing to him Susie?" shouted Ellen. "You should be punished for what you are doing to him, his balls are almost. I then took a gentle bite of his cock shaft. I looked up and saw he had his eyes closed leaning back. I gripped his hips and forced him to turn around. He looked surprised but then realised how he would soon be facing. With a grin he let me twist him to be looking away from me. More specifically, he was now showing his thong-clad arse to me.I gripped both buttocks and kissed his left then right cheek. I kneaded his arse and pulled it apart, pushed it together. I saw the thin strip of thong. " I guess so too." Paula hung her head in sadness. We ran off back to our roomand let ourselves in. "Hi guys, did you hear his shpiel?" Mom asked.I answered, "Yeah, it was about this new waterfall they installed in thepool. If you pass under, it changes your gender." Mom and Dad looked at eachother. "Permanently," I added. "Paula and I both want to try it. Can we?" Er...I'm not sure. It really is permanent?" Dad asked. I nodded. "Well, ifyou both *really* want to, and your mother agrees..." Dad. I start to kiss your neck and back. I grab your ass tightly. Then I moved down between your legs and start to lick your ass and then your boi puss! You moan a few sweet little moans as you start to press your hips back to my face buried between your ass cheeks. You didn’t mean to, but when you pushed your hips back your balls and cock become visible and were very close to my mouth. I couldn’t help but notice. I ignored seeing them and just focused on the delicious asshole I was tasting. I was.