Sirius laughed. "Deal, I promise. Next time I'll escort you."
The idea of poor Harry having to venture into Severus lair, alone, made him slightly queasy. And what with his own outlandish behavior with said teacher earlier that week he knew how slightly creepy the man could be.
'fixated on my ass'
Not exactly what Sirius wanted to hear. He knew that Severus was a little weird, but he'd gained some respect for the man since he'd been a double agent for the Order. The last thing he wanted to worry about was Severus becoming... well, as some people would say "like a funny uncle."
"Did he really now?" Sirius visibly shivered. "I'll definitely be with you next time. No worries." He winked and laughed. "How's your old man? Haven't heard from him in a few."