This sauce is very common in many world cuisines. Garlic sauce based on sour milk (or on natural yogurt) is traditional for the peoples of the Caucasus. It is used during feasts and for various national rituals. Each nationality has its own variation of this dressing. In this recipe, I took as a basis the Adyghe sauce - "shkhushyps" ("shhu" - sour milk, "shyps" - sauce, gravy). He added cilantro greens and tops of hot peppers (this is from the Ossetian cuisine "tsakhton"). The resulting mix was not only for me.
Crush the peeled garlic in a mortar, adding salt.
A young (not stiff) whole bush of hot (bitter) pepper (all tops: leaves, soft stems and ovary of pods) simmer in boiling water for 2-3 minutes. Then grind everything together with cilantro in a blender: you can make it into a homogeneous mass, or leaving larger fractions to your liking.
Dilute with sour milk, combining sour cream, crushed garlic and green pepper mass, add red ground chili pepper. To stir thoroughly. The sauce is ready.