I was so proud of her. We had a graduation party for her. The BBQ going, the pool was filled with her friends. All those young bodies in their litt...e bikini's. The boys trying to hide their ocassional hard ons. The girls checking out the boys. Teasing them. Their tops would “Accidently” come off. Then a couple of the girls feeling the effects of the beer, and sun and hormones raging, started to pants the boys in the pool. All I could do is sit back and enjoy the show and fantasize. I. ” I sank back into the water next to Thu – we all laughed together.As I dipped back into the warm bath, Thu climbed out and sat on the toilet with her legs apart, massaging her tits as she started to piss, “It must be the wine. It’s like being pregnant again – weeing every few minute.” It was an overstatement but that didn’t matter, “or maybe darling, it’s your sexy story.” Thu pissed an arcing stream into the porcelain. She washed herself with the spray hose and resumed her position back in. She was wearing white lace stockings with nothing else, except that other stocking still bound over one wrist. Evidently, I had loosened it enough earlier for her to escape her binding. The long thin body looked very feminine lying there on its side; the sleek, teenage female curves covered with her tight, youthful, perfect skin was a sight to entice any man that still breathed.Not for the first time, I felt jealousy seep into my heart; not towards my daughter, mind you, but towards time. My. With the angle as she was leaning forward, I felt extra pressure around my knob and shaft. My mind went to my first level maths lessons, on cylindrical and conic sections; what was happening was that we were inserting one cylinder – my prick – into another cylinder – Cathy’s vagina. If the axes of the two weren’t collinear, then rather than being presented with what was basically a circular opening, my prick was trying to enter an ellipse and the minor axis was smaller than the diameter of her.