So, long story short, im married, was over at my best mates house for a party for the night, everyone was asleep, well I thought they were. His younger sis is pretty damn hot. I went into the bathroom after she’d had a shower and found her black thong. I couldnt resist. I picked it up and smelt it, it was so damn good, instantly hard. I could stop from sniffing and tasting it, I pulled out my now dripping cock and started stroking when the bathroom door flung open. There she was, standing there in her underwear, while I had my cock in one hand, her freshly worn thong in the other. I froze. Couldnt say or do anything, she walked in and shut the door behind her. I quietly apologised, I was blushing like hell. She looked at me for a second then told me to keep going. I was like what? She said keep going or ill tell. So I continued while making eye contact with her, until I blew probably the biggest load of my life into her thong. She quickly snatched it off me, took off her underwear and put the thong on. She said it was hot that her bro’s married friend was into her that much. She gave me back the thong the next morning. I have it hidden from my wife and still use it to jerk off