"Nope." He's not worried it's a dream - this is way nicer than either of their dreams, he's sure - and he's not worried he's going to forget it. The way Clint's heart feels beating against his palm is... quite possibly the best, most reassuring, thing he can even imagine right now.

"You should let me take the couch tonight, though, otherwise you're going to have a hard time walking tomorrow, much less moving at speed."

Stiff. All he means is Clint's going to stiffen up overnight and more so if he's sleeping in cramped conditions.