About two weeks ago my wife's sister and her husband visited us for a braai. We were enjoying ourselves and I noticed that she was drinking quite heavily. At one stage when she went for a wine refill I walked in with her to the kitchen leaving the other two outside. In the kitchen I started flirting with her and at one stage felt up her bum. She seemed quite willing so I went behind her rubbing my cock against her bum while fondling her very large breasts. She started moaning so I dropped my hand down to her crotch and stuck it up under her shirt feeling her panty covered pussy that was quite wet at the time. I heard my wife come in and quickly moved away busying myself pouring drinks. The next day I phoned her and at first she tried to deny that anything happened making out as if she couldn't remember any of what happened. At one stage I got fed up and called her a fucking teasing slut. This opened doors for me to my surprize. She invited me over and as I can come and go during office hours I had the opportunity to go to her while her hubby was at work. On my way there I realized that she had the need to be dominated and spoken down to. Arriving there I greeted her by saying " so how is my horny fucking slut today" This melted her into my arms. Soon she was on her knees in front of me sucking my cock. It seemed that the rougher I treated her and the cruder and dirtier I spoke to her the more she got turned on. I grabbed her head and started fucking her mouth with meaning, calling her my whore etc. to which she responded with gusto. Afterwards she confided to me that she loves being dominated and treated like a slut but that her husband wasn't really into it. Now I call her regularly and when we have the opportunity I treat her like the slut she is and she loves it.