Combine the tequila, Cointreau and lime juice in a bowl. Divide between a popsicle mold, then top with club soda. Add some fresh lime slices. Insert popsicle sticks and place in the freezer until frozen, about 3-4 hours.
Unmold the popsicles by running the popsicle mold under warm water - make sure not to get water INTO the mold!
To store, wrap each popsicle in wax paper and place them in a freezer bag. Store in the freezer and enjoy whenever you like!