Crowley had to laugh at that as he slid the sunglasses back on. "Really, you're apologizing to a demon for having an adverse reaction?" he teased, finding the situation genuinely funny. "Oh, wait until I tell Zira about this." And, okay, he might not bring it up unless Aziraphale finds out about the giving Sam blood part, and he might just tell him himself about the donations just to tell him about the apologizing.
But after he got a hold of himself and was down to just chuckles, he really did find it funnier than most beings would, after all, he managed to ask a simple question. "So. Who'd you think I was for a minute there?"