There was a four year gap between her sister and she and her brother. Her mother had never said much about it. Sammi wondered how hard her mother had ...tried to get pregnant. She had been in the middle of her movie and television career at the time, and pregnancy just didn't mix very well with that. Sam had told her once that he thought their mother had just let chance take its course. Sammi wasn't so sure, but she could see her brother's point. Neither of them looked like their Dad, nor did they. She got off my leg and planted her jean covered pussy right on top of my cock which by now was pointing up towards my stomach in my own jeans. I reached up and began playing with her stiffening nipples. I slightly pinched them as I rolled them between my fingers. A soft moan escaped her lips as she leaned back planting her hands on my thighs and began grinding back and forth against my cock. As pleasurable as this felt, it started to become painful as the clothing rubbed against the underside. She was beaming like a new bride.As I started signing, my wife told me ‘They are very happy,’ and the documents they had there had us buying the home severally as unmarried people.Faith went up to ‘Pick out’ her room.During this, I casually mentioned we came from the home we bought for my brother, his wife, and her sister. DD mentioned that the wives were sisters. Gloria thought that was very romantic, unaware of the likely very loud sex parties we would be having at either of the homes just. She didn't notice Greg and I standing just outside of the kitchen entrance."See Dawn, I told you my tits were fucking gorgeous..........Oh fuck"!Shelly then cupped both of her boobs and shook them towards Dawn."Well hi honey" I interrupted.Shelly looked over towards the entrance and immediately turned red with embarrassment.She quickly folded her arms over her chest to cover herself."I.....I didn't even hear you fucking guys come in". She stammered.Dawn sensing the embarrassing tension chimes.