1 seedless watermelon, chunked
ice as needed
1 (750 milliliter) bottle vodka
4 cups watermelon schnapps (such as watermelon Pucker®)
1 (2 liter) bottle lemon-lime soda (such as Sprite®)
Place 1 chunk of watermelon into a juicer; juice, removing as much pulp as possible. Repeat until all of the watermelon is juiced.
Fill a glass 1/3 full with ice; pour in watermelon juice. Pour in one 1 1/2 fluid ounce shot of vodka and one 1 1/2 fluid ounce shot of watermelon schnapps; top with lemon-lime soda. Repeat for each cocktail.