Sam wandering around the apartment carefully was quite entertaining, Dean decided - he looked ridiculous, seriously - but it also was kinda awesome, ‘cause it meant Sam was taking him seriously and Sam didn’t want to kill him by mistake, and if he’d been himself he would have brushed that off with a joke of some kind, an aw, you really do love me, or something, but as it was he couldn’t, and didn’t really feel like he needed to, anyway. Just this once.
When his brother noticed him, his reaction was even more comical, and Dean definitely would have been laughing his ass off if he were himself right now. Seriously. He was so genuinely surprised and confused, and Dean almost wished this was some kind of joke just so he could have done something so epic it would beat anything his brother could throw at him.
Unfortunately, that was not the case.
Sam was talking, then, and, yeah, he could understand him, but he wasn’t sure how the hell he was supposed to communicate in return. Squeaking all the time was totally out of the question - it was annoying, and he sounded dumb and too 'cute', and, um. No. Dean Winchester did not do the small-and-fuzzy brand of cute, even when he was a friggin' chipmunk, okay? So he just kind of tilted his head, attempting to make it known that he did, in fact, understand his brother, even as a stupid rodent.
>“Maybe I should..." - Sam started moving again, then, and Dean instinctively flattened himself closer to the carpet uneasily, the new rodent-like portion of his brain panicking and getting ready to flee - “Better?” - and then Sam was still, sitting on the carpet, and Dean relaxed, sort of. This whole thing was stupid, he wasn’t supposed to be this small and this scared. This was Sam, Sam wasn’t scary!
Screw this.
He moved forward, almost creeping over to his brother, stopping in front of him to look up at the friggin’ giant, and then he proceeded to climb up Sam’s huge leg to sit on his brother’s knee. He totally wasn’t scared, okay? And this was proof of that, or a way to ignore all the ways he actually was kind of freaking out... Or something.