This is such a fun drink to make with friends or family in the summer. My wife and I made this on the outdoor patio of our apartment and it was such a fun way to enjoy a nice summer day.
Scoop out the watermelon flesh using a melon baller or spoon. If you use a spoon, chop the watermelon into bite-sized pieces. Try to scrape out as much flesh as possible. Watermelon juice will build up at the bottom of the rind, leave this in the melon.
Add the chopped strawberries, peaches, melon balls, milk, cranberry juice, and ice to the empty rind. Gently stir to combine.
Pour the carbonated water around the edges of the watermelon so less fizz escapes then add a little bit of syrup from the canned peaches. Gently stir to combine then serve.
Notes
My favorite part of this drink is that the watermelon absorbs some of the carbonation so they taste fizzy. For some reason, the other fruit does not do this, so it is always a treat to bite into the melon.