My best friend has a really smoking hot younger sister (1 year younger). I was round his house and staring at her as per usual and I just got so horny.

Everyone was downstairs and I said I needed to speak to my mum on the phone upstairs or some crap, so when I went upstairs, I entered her room and found a dirty used bra and knickers.

I took them into the toilet and sniffed the knickers and wrapped the bra around my cock. I masturbated and came. I wiped some of my cum on her hung up dressing gown, just where her ass would be.

I stole the knickers and the bra and still wank over them today.