9 cups water
2 cups white sugar
4 green tea bags
1 (12 fluid ounce) can frozen lemonade concentrate
1 (12 fluid ounce) can frozen orange juice concentrate
12 fluid ounces vodka
12 fluid ounces gin
1 (2 liter) bottle lemon-lime soda (such as 7-Up®), or to taste
32 maraschino cherries, or more to taste (optional)
Combine water, sugar, and green tea bags in a large pot. Bring to a boil and dunk green tea bags several times in the boiling water. Discard tea bags. Stir in lemonade and orange juice concentrates until dissolved. Remove pot from heat and allow mixture to cool.
Stir vodka and gin into the cooled tea-juice mixture. Pour mixture into a freezer-safe container and freeze until slushy, 3 hours to overnight.
Stir slush to evenly distribute the alcohol. Fill small glasses with about 1/4 cup of slush; top off with lemon-lime soda. Garnish each drink with a maraschino cherry.