If Klaus had been the least inclined to find Eroica amusing, he was reasonably certain he would have been so now - Klaus might not be a fan, exactly, but he was familiar with the way 'Father Christmas' supposedly looked (which was like a fat, white-bearded relative wearing a costume) and Eroica looked ...
"Too skinny," Klaus said, realizing too late that what he really should have said was: 'Go away'.
"Feed me?" Eroica said, hopefully.
He did look a little bit hungry, now that Klaus has gotten a few moments to look - which, obviously, was no problem of his, but then it was Christmas, and cold, and surely even Eroica would keep his hands to himself if Klaus kindly offered him a hot meal?
(Of course, when he woke up the next morning, Eroica had somehow redecorated the entire Schloss, with lights and holly and strategically placed mistletoe, and Klaus decided that next year, he'd take that mission to Siberia and be glad of it.)