Prepare the cherries: Prick fresh cherries with a knife tip or thaw frozen cherries and reserve the juices.
Combine ingredients: Pour alcohol into a 2-quart jar. Add sugar, cover, and shake until dissolved.
Add cherries and spices: Add cherries, reserved juices, cinnamon stick, cloves, allspice, and nutmeg. Cover and shake to combine.
Let it age: Place the jar in a warm, bright spot for 1 week. Then transfer it to a cool, dark spot for 6 weeks to 3 months.
Strain the bounce: Strain the mixture through a fine mesh strainer or cheesecloth into a large bowl, discarding solids.
Settle the liquid: Let the liquid stand overnight to allow sediment to settle.
Store: Carefully pour or ladle the liquid into a clean 1-quart jar, leaving sediment behind. Store tightly covered at cool room temperature or in the refrigerator.