Apparently he had his potty mouth moments long before Gokudera came along (though I'm not sure if that would actually be a relief to his mother or not XD).

It was so unexpected, too. I was busy looking at Kyoko, and then I suddenly took a closer look at Hana next to her and nearly did a spittake. Except I wasn't drinking anything, but if I HAD, then it would have been disastrous.

Yeah, they do, kinda. Those were simpler times. ;_;