The first time I got someone besides my brother to have a accident

This was back when I was a freshman.
We were lined up to head back to class when the guy next to me started getting restless. He was doing the pee dance, crossing his legs and grabbing his crotch. When he caught my eye, he mouthed, "I gotta go bad." Something about it sparked a weird impulse, and I told him, "You probably won't make it. Just go." I don't know what possessed me to say it, but he looked at me, seemed to consider it for a second, and then... yeah. He let it happen.