I like to wait until no one is at the drink station, and then shotgun a glass of wine (full to the brim) and then refill it really quick without anyone noticing. Once refilled I casually mingle with aunts and uncles and cousins, sipping the wine. Once that glass is gone I repeat the process, so it looks like I'm going as slow as everyone else but its really 2 or 3 times faster. I do this every gathering for the season.