Peel and core pineapples. Slice each pineapple into 5-6 rings. Cut each ring into 4 pieces. Fill large decorative beverage dispenser with the cut pineapple. Stack pineapple like bricks in alternating rows. Fill with vodka. Make sure pineapple is fully covered. Let sit a minimum of 5 days before seving.
When ready to serve, fill martini shaker with ice, add vodka from dispenser, shake well and strain into a martini glass.