Slice the watermelon quarter, then cut off the peel and dice the watermelon pulp. Rinse the lemon balm, shake it dry and pluck the leaves from the stems. Rinse the lime under hot running water, dry with kitchen paper and cut into slices or quarter. Put the ice cubes, lemon balm leaves, lime slices or quarters and the watermelon cubes in a glass carafe. Top up with the tequila, rosé wine and mineral water, stir briefly and then serve immediately.