There very certainly is something there in Toshi's reaction. It isn't that he has discomfort about someone being in his personal space, necessarily. He quite likes sharing personal space usually. Mettaton just has a gravity that makes him nervous.

A gravity, and you know, a host of qualities Toshi finds attractive.

He opens his mouth, quickly closes it, and blushes darkly, tugging his hat down to hide his face. "Oh. Right. Of course." He's so stupid he's such an awkward doofus. Quietly, he adds, "I am, though." Wild Tiger's biggest fan, of course.