Interesting question. I'm sure at some point I've made sweet, sweet, swivel-hipped, jazz-infused, pizza-fueled, dong-vag conjoindery with my pants still around my hairy, sweaty ankles. That's gotta be up there, but I guess I'm barely 'in' pants in that scenario.
I've had some pretty impressive athletic accomplishments over the years, but I'm pretty sure they were all in short-shorts.
Geez. This is tough. I've written books. That would be impressive to most, I guess, but I'm rarely wearing anything while I'm writing let alone pants. In fact, if I have to wear pants at all, as soon as I come home I take them off.
The hardest part here is just figuring out what the greatest things I've ever done have been. I'm sure if I could come up with a few, some of them had to be in public during the winter.
I've got it. I ejaculated in my pants on a few occasions. Once, in particular, while I was with a girl and I was touching her boobs. She was completely naked, and I was still fully clothed. And then I pearled my khakis. It was great!
Short Answer: I was wearing jeans, but 'cream your jeans' is overused, and 'nut your slacks' didn't quite have the right feel. Though one time I did spooge my cords...