I knew he was playing with himself but I didn't say anything about it. I was also getting a little turned on but I grabbed a blanket and covered mysel... up with it. I was only wearing my underwear and I started rubbing my own cock too and I didn't think he could see what I was doing. After a few minutes, he also got a blanket and covered himself up and told me that he was a little chilly and needed to warm up. I of course knew better as I was fondling myself just like he was.After a few scenes. He reached to the door and gently turned it and couldn't believe his eyes. His sister Brandy, lay across her bed, her nightshirt pulled up exposing her fat 38-inch breasts and as he looked down he couldn't believe how wide her legs were spread. And the thing that really caught his eye was the 10-inch vibrator she was ramming in and out of her pussy.Tim knew she masturbated, but had no idea that she ever did things like this. As he watched he could feel his cock filling with blood. He had never. "What do you want?" His hot breath on my neck sent shudders coursing through me. "I want you to fuck me." "Do you?" He twisted my nipple painfully. "I do." Whimpering, I turned my head to kiss him. He tangled a hand in my hair and jerked my head back. "But I'm not done with you." He tugged my shirt over my head and turned the chair to face him. He grasped my wrist and pulled my hand from beneath my skirt. My hips bucked in protest. My fingers were visibly wet as he brought them to his lips. What is the percentage of the population that uses birth control? 10%? 90%? Let's say 75% use birth control and it is 100% effective, which is absurd, I can tell you from personal experience. So the 11,250 figure is produced by the 25% that do not use birth control. That means that 45,000 couples will have sex today, excluding all the groups I already mentioned.We all know women have cycles, and are fertile for, what, a week or so? Let's say 50% of the time. So those 11,250 births are the.