Rhassoul clay is a natural skin-firming ingredient. It contains minerals like silica, magnesium, iron, calcium, potassium and sodium that helps to firm and tighten sagging skin, including breasts. Mix 2 tablespoons of Rhassoul clay in powder form with enough water to make a smooth paste. Apply this paste onto your breasts and allow it to dry. Rinse it off with lukewarm water. Follow this treatment once a week.