Add the honey and your red pepper flakes into a small saucepan.
Warm the mixture over low heat just until it begins to form small bubbles or a gentle simmer (about 1 to 2 minutes), watching closely so it does not burn or boil over.
Remove the saucepan from the heat and let it steep for 10-30 minutes. The longer it steeps, the spicier it will be.
Pour through a fine-mesh strainer into a clean glass jar or squeeze bottle to remove the pepper pieces.
Video
Notes
Store in an airtight jar or squeeze bottle at room temperature for up to 1 month, or in the fridge for up to 3 months (the honey won't spoil, but flavor and heat mellow over time). It's a good make-ahead gift: make a big batch and jar it up.