Dispicable

I'm 47 and for the last two years have had a 26 year old girl (Dana) living with me. It was she who came on to me, flirting with me long before I ever had sex with her. She is not a very pretty girl but does have a decent body. I let her move in only for the sex she supplies me and her willingness to please me. I have but to ask and she accomdates my every wish. She is often aggressive and without me asking gives me oral sex or masurbates me while watching tv at night. She is intelligent but as far as sex is concerned is the most uninhibited girl I have ever met. She is open to anything and nothing seems to embarrass her no matter what I do to her or what she does to me. At the end of this past Janruary she asked if her sister (Diane) could stay in my spare room. It was only supposed to be for a month or so but she is still here. Her sister is even less attractive and also is very thin, flat chested and I think anorexic. Less than a week after her sister moved in Dana undid my pants and jerked me off with her sister sitting in the chair across from us. I thought it odd she would do that with her sister watching but do admit I was turned on by it. Diane never said anything but sat there smileing as Dana did it. The very next night Dana gave me oral sex as her sister again witnessed it. I asked Dana why it didn't bother her with her sister watching and all she said was Diane liked watching us. She asked me if I was ok with it and I only said it made me hot with her sister watching. Within a matter of weeks Dana began undressing me telling me Diane asked her to do it. Those first few weeks Dana would blow me and jerk me off and then we began having intercouse with Diane sitting on the chair. Both myself and Dana get naked a few times a week on the sofa with Diane in the room and aside from oral sex and masturbation I have had anal sex with Dana many times. Dana actually tried to get Diane to take her clothes off also but she won't ever do it. She does masturbate while watching us but still won't take off any clothes. A month ago Dana did get her to masturbate me and now she will do it to me about once a week. She has tiny little hands and now does talk sometimes while she is jerking me off. She is one strange broad and all she seems to want is to watch Dana and I have sex. Dana is the one who gets Diane to masturbate me all the time and always has to coax her to do it. I only saw Diane naked once and her body is horrible, almost like skin and bones. We try to get her to eat more but she just won't. She likes seeing me naked and having sex with Dana but I can see why she is ashamed of her body. I like it when she jerks me off but she won't give me oral sex yet.