He should be angry about it. Sirius certainly is. But that's a conversation for another time.

"Of course they're a secret admirer. I have countless," Sirius says, bold-faced and cocky, though one corner of his mouth is twisting up in a grin. "And my ego i-uwarrgh --" With a funny wriggling sort of movement, as if he's just touched something slimy, Sirius scooches a few inches over on the desk. "Knock that off, you little shite."