It was about 4 years ago now, about a year before i met my current GF.
I remember it was summer time and I was horny as hell. Of course I remember her being dressed in knee length denim skirt and a tight top, just enough to tease a bit but not show too much. We were bored and I kept trying to get on her, kissing her, groping her, and the like. We had played lightly in bdsm and forced femme a few times before, but it never got too serious, nothing nearly as degrading as some of the things i've done since. Anyhow, realizing I was horny and at this point puddy; she said, "well why don't you put on a pair of my panties and let's have some fun." So I figured it would just be hanging out, eventually sex, etc. I put on a pair of pink bikini panties she had, but then she made me switch to a black cotton thong. Then she told me I was hanging out and looked funny so to put on some shorts. At this point I was raging hard and flopping out all over the place.
After some light teasing she said she was hungry, and she wanted to go get something to eat. Horny bastard that I was, I tried to get her to wait, but she said alright let's go, and I went to change, but she told me not to, that it'd be fun.
So I went out and we ate at the local mall in the food court. As we sat there eating she kept teasing me, rubbing my leg, or whispering things like, I wonder what'd happen if I snapped your thong and pulled it out right now..or..what if i told that group of girls you had a thong on?."
Of course, I was still hard as fuck, but damn nervous as well. She didn't end up doing anything as it was all in good fun.
Later she took me home, spanked me a bit for fun, teased the shit out of me awhile longer, made me go down on her in the thong, and then finally we had sex.