Dave practically melted, because he was a sap and seriously, that was adorable.
Dave had to clench his hands (ow, bad hand, no clenching) to keep from wrapping an arm around Cas or lacing their fingers together or anything else ridiculously coupley. But he could totally pet the adorable kitten and maybe kiss it between the ears and give Cas meaningful looks. He leaned in closer and whispered, "My place?" and was super proud that he managed to keep the Blushing at around fifty percent.