Generally, I try not to do anything else when burning a disc. Granted, I might be rendering video, but I can allocate that process to low priority mode - and I don't care if the fps goes down occasionally. In a game, you don't want sudden slowdowns of course, and measures to eliminate skips (changing process priority levels perhaps) might cause buffer underruns. Maybe.
Got a disc to burn? Get it ready to burn, and when you need a bathroom, food, or whatever kind of break, have the disc start burning then.