When he's sure they're not being followed, or at least closely followed Cuthbert finally gives up on the song.

"How are you feeling? You were lucky to have that wrapping with you, although I will take a moment to mourn the loss of a good addition on thee."

He's trying to ignore his own padding because he thinks it looks ridiculous on him. But obviously he's feeling more confident if he thinks it's safe to joke again. He's still getting a feel for everything around them, and feeling frustrated with the general lack of cover.