Mix orange juice and tequila together, then pour into prepared freezer pop bags. Seal and freeze for 4-5 hours.
Once frozen, place one Maraschino cherry in each bag and fill up to the fill line with grenadine. Place into the freezer again and freeze for at least 1-2 more hours.
Notes
Using a funnel or a measuring cup with a spout can help prevent spills while pouring the orange juice/tequila mixture into the freezer pop bags.