Pour the first three ingredients, taking a shot glass as a measuring instrument, in a minimum 22 oz glass container with a lid. Add ice and shake vigorously for 8 seconds. In a long glass, with previous ice, pour the mixture, holding the ice in the glass jar with a small strainer and complete with soda. Stir with a long spoon from bottom to top to mix evenly. Decorate with lemon peel and tarragon leaves.