1 seedless watermelon, halved and sliced
3 cups water
1 (15.25 ounce) can crushed pineapple
1 (12 fluid ounce) can evaporated milk
1/2 cup shredded coconut
2 tablespoons white sugar, or to taste (optional)
1/2 lime, juiced
Grate watermelon with a fork from the rind into a large bowl, leaving no large chunks. Stir water, pineapple, evaporated milk, and coconut into the grated watermelon. Add sugar; stir until dissolved. Squeeze lime juice into the watermelon mixture.