Put your vanilla vodka in a large pitcher and add one or two cans of pineapple juice. I only add one, sometimes one and a half. That makes it perfect, but if you want it to be a little weaker in the alcohol taste add the 2 whole cans of pineapple juice. Get a glass filled with ice cubes, put your mixture of vanilla vodka and juice over the ice , add a splash of grenadine, and you've got a pineapple upside down cake mixed drink! They are reallllyyyy good!!!