Spring is here. It's time to get loose. Emphasize the casual by abandoning ceremony and prepping your cocktail station beforehand. Keep options open by offering drinks for different tastes. And by all means encourage partygoers to serve themselves and one another. What better way to get people to mix? The tools here are simple and effective at putting drinks into guests' hands and then quietly getting out of the way. Wine Spectator's Jack Bettridge explains.