He blushes harder, not making direct eye contact
"U-u-um-"
"Mh...~"
He melts into Alvin, Alvin can feel him relaxing, eyes lowering-it is at this point I feel I should mention that although he is taller than Alvin, Darcy is pretty light-he's very slim, a little bit gangly for lack of a better word-long limbed-Alvin could most definitely pick him up if he wanted to, and it's pretty obvious when you touch Darcy-he's been somewhat malnourished.