Natasha / Clint
Clint didn't know why Tony -- the kid one, not that other one that he hadn't met yet -- was the only one with a hot tub, but he didn't really think to question it either. It didn't seem like the sort of thing that he would ever have personally and so he didn't think into it much further than that. "My house has three floors," he said, like that possibly explained something (It didn't).
Still, he pulled his shirt off and tossed it aside without much deliberation at all and then chucked his shoes and socks off too. Because if someone had a hot tub, he was sure as heck gonna try it out. "Maybe everyone's just got something different. You wanna go in?"