It was clear that Envy's presence made the other guy uneasy, and while that wasn't intended, he didn't really care much, unless that were to subsequently upset his 'host', which wouldn't bode well for him.
He offered a friendly smile, subtle enough to not come off as fake and let them finish up as he poked at his food inconspicuously. It probably would be best to be in seclusion, were anything particularly relevant to be revealed in their conversation. But with his experience in being secretive, sometimes right out in the open was the best place to keep things hidden.

He raised an eyebrow, smirking slightly and leaning on his propped up fist when she mentioned making an offer.

"Oh? I'm listening."