Mince the garlic as fine as you can, or grate it on a microplane so it disappears into the sauce.
In a bowl, measure the gochujang, rice syrup, soy sauce, and rice vinegar: 2 parts, 1 part, 1 part, 1 part.
Whisk hard for about 30 seconds. The mixture looks streaky and broken at first, then suddenly turns smooth and glossy.
Stir in the toasted sesame oil and the garlic.
Add water 15 ml / 1 tbsp at a time until the sauce falls off the spoon the way you want it to: thick and slow for a glaze, ribboning for a dressing.
Let it sit 10 minutes, then taste. Add vinegar if it's flat, rice syrup if it's harsh, a splash of soy sauce if it's dull.
Transfer to a clean jar and refrigerate. It keeps about three weeks and gets rounder after a day.