Combine the lemon juice and sugar in a large glass and stir until the sugar dissolves.
Add the raspberries and mint to the fresh lemon juice and lightly mash the raspberries with the back of a spoon to release some of their juices. Add a few ice cubes, the water, and tequila, and then give it a good stir and enjoy.
☞ TESTER TIP: If the cocktail is a little strong for your tastes, add a splash more water or soda water to dilute it.