Add in vodka (I start with 1/2 cup), mix well and taste. Adjust sweetener as desired.
Serve over ice!
The longer it sits, the better! Make an hour or two before serving and let it sit in the fridge.
There are many gluten-free vodkas out there, my two favorite are Ciroc Vodka and Tito's Handmade Vodka. Tequila and rum are generally naturally gluten-free. Read labels and be cautious of added flavors.