Add hot water, honey, and maple syrup to the slow cooker. Stir until dissolved.
Add cinnamon sticks and cloves.
Pour in whiskey, rum, and lemon juice. Stir to mix.
Cover and set slow cooker to low for 1–2 hours to infuse flavors.
Switch to warm setting for serving.
Ladle into mugs, garnish with lemon slices, and serve hot.
Notes
Do not let the punch boil, as it can dull the citrus flavor and reduce the spirit’s character. Adjust sweetness by altering honey or maple syrup amounts. Remove spices if they become too strong.