Have always been attracted to my youngest sister. Shes 5'10", long legs very slim and small breasted. One day when my wife was gone we were in the hot tub drinking and I confessed that I've always thought she was hot and I kissed her. In return she put her hand down to my swim trunks and started rubbing my cock which was already hard. I pulled it out and she started stroking it I undid her bikini top and started sucking on her very erect nipples. Then I put my hand in her bottoms and finger fucked her to orgasm. I then leaned her up against the hot tub and entered her from behind, riding her fast and hard til I came into her pussy. We got ourselves put together before my wife came home. Since then we have fucked many times, a few times almost getting caught by my wife or my daughter. Cant wait til the next time