I think I am one fucked up dude
My sister is 19. We have never been close or in any way sexual with each other. Anna keeps herself fit and she runs three or four times a week. This particular day we had the house to ourselves as our parents were having a Valentines weekend away. Anna had gone for a run as usual. The seafront at Cairns is great for that. Miles of totally flat, really good running then round the lagoon at the end.
Anyway, when she got back home, she headed straight for the shower, kicking her clothes off as she went until just as she got to the bathroom she was in just her bra and panties.
I don't know why, but I started to pick her clothes off the floor. More to be tidy than anything else. When I picked up her top, I noticed something I had never noticed before. The scent of her sweat. It was sweaty..(duh.. obviously) but also feminine. I put the armpit to my face and breathed in deep. BANG! Instant hardon. I rubbed myself outside my pants for a few moments before I picked up her shorts. They were damp to the touch. I smelled them too. BIG mistake!!! Not only sweaty, but also THAT special scent of pussy. I had my cock out in an instant and was smelling Anna's crotch of her shorts. I hadn't thought about what to do when I came, I just had to go for it. I didn't even hear the water shut off in the shower. Then the bathroom door was open and Anna was standing there, towel wrapped round her staring. I figured I was totally dead and she would tell our parents. Instead, she went back into the bathroom. She came out with her panties and a towel. 'Here. Try these.' She handed them both to me and went into her room. The crotch of her panties (which were a dark blue pair of bikini type) was white with her pussy stains and black with her sweat. I smelled them and licked them and shot a huge load into the towel.
I put everything in the laundry and knocked on her door. She invited me in and I sat on her bed and said 'Umm Anna.. er.. I dont know why I did that.. I just..' She said. 'look. I get it. OK? I'm not grossed out, just don't let mum and dad find out ok?' Then she told me she had just jilled off thinking about me cumming. It was a difficult conversation, but it ended that I could use her panties from time to time if I wanted. She DID ask that maybe I would cum into them and give them back to her. I guess it's erotic for her too.