I had been going out with my boyfriend for a few months and I knew he enjoyed a horny phone sex chat, that didn’t really bother me; it quite turned me on in fact. We were looking after my Dad’s house one week as he’d gone away, and I’d gone out for the afternoon. When I got back the back door was open which was unusual, I went in and heard my boyfriend on the phone talking utter filth. I peeped through the crack of the door and saw him with a pair of black lacy knickers in his hand wanking away, it took me a few minutes to realise that these knickers weren’t mine, they were my Dad’s girlfriend, and he had a photo on his knee which he was looking at. I didn’t say anything as I needed time for it to sink in. I’d spoken to Knicker Lovers myself and knew how much they get guys turned on, and when I was chatting on the phone, the guy told me to go and put on a clean pair of her knickers and masturbate in them, which I did as he listened, this might put a stop to his Knicker fetish the next time he gets them out of the washing basket he will think they are hers, but really they smell of my pussy, not hers! It backfired a bit really because he saw me wearing them, and he knew instantly they weren’t mine, and the fact that they were hers gave him an instant hard on, he fucked me so hard and so desperately I thought he was going to pass out, it certainly perked up our sex life though.