I held it still and brought my other hand to my clit and quickly rubbed it, pushing down hard, no pretense of subtlety at all, just gritty, hard frigg...ng, trying to get myself off fast, now, and my pussy started to throb and spasm around the dildo, like it would around a real cock and my back arched, pushing my head back, lifting my ass off the bed, pushing my pussy upward into the air, trying to take the hot pink cock deeper into it and a flash of warmth shot through my body and I collapsed. “I’m not bothered if you’re both fucking my daughters or niece, its natural, infact I’m pleased it’s you and your friend instead of some dickhead, I like you two, you seem like good lads”. He continued as he put the cover on the filter.He went into the conservatory and switched on the pool heater, then came back out with 3 chairs and some beers.It was a bit too early for me to start drinking so I just lay beside the pool in the sun.After what seemed like 30 minutes I sat up, David and Ray were. I was surprised even, that the neighbors didn't hear her. We kept at it, off and on, most of the night. If I got soft in between, during our breaks, she would give me a hand job to get me back up. But, we finally finished around 5 in the morning. When I woke up, around 8:30, she had already gotten up, taken a shower, and was making breakfast for us. She wanted to go ahead and keep my original plans of an excuse to come down, so we got ready and went to the amusement park, and spent the day.. Jessi's eyes went wide when she saw what I was doing, and how my sister moved closer to my bed. My sister's eyes were still glued on my penis, as she sat down next to me and took over the job of playing with my cock. My hand immediately found her vagina, and began caressing it through the cloth of her bikini bottom. "Heather? What are you doing? That's your brother!" Jessi protested. Heather looked up at her."And?" Was her only statement, as she gripped my cock firmly now and began jerking it.