It is a brow styling product designed to give groomed, fuller looking, natural brows.
Brow soap was created to style and hold brows in a natural, fluffy desired shape. It is perfect for sparse brows or for those wanting a bushy look.
Spray some water onto the soap, (not more than once because you don’t want the product to get too wet) Rub the spoolie to gather some product, until it becomes quite tacky then coat your brow hairs. Leave for a minute or so then go back and shape.