1 (1.75 liter) bottle raspberry lemonade (such as Simply Lemonade®)
1 1/2 cups watermelon vodka
1/2 cup coconut-flavored rum (such as Malibu®)
1/2 cup triple sec
Pour 2 1/2 cups raspberry lemonade out of the bottle into a glass measuring cup.
Pour watermelon vodka, coconut-flavored rum, and triple sec into the bottle; stir to combine. Fill bottle back to the top with raspberry lemonade from the measuring cup. Refrigerate until serving.