Once seated himself, Severus has the good grace to fill Lucius's glass. It's at this point that his well of good manners runs dry, however; it was never really full to begin. This is all a matter of making a good show of being civil (or more civil than he was last time), and he doesn't have the capability to go overboard, much less the desire.

Lucius can help himself to more if he wants it.

"If you wish to raise a glass to my comings and goings, do it if you see the back of me for good," he replies dismissively. He doesn't hold out hope that it'll happen, and that flat disbelief bleeds into his tone. 'If', not 'when'. It's with that comment that he reaches for his wine, falls still, and glances around. It's a little too close to the subject that has been on his mind since before his abrupt departure.