A mixing applicator for mixing a fluid substance with a solid substance to obtain a resulting substance having a desired consistency, comprises: two valves slidably displaceable within a hollow elongated barrel and sequentially arranged along a longitudinal axis, the valves having a third cross-sectional shape being complementary to a first cross sectional shape, thereby providing fluid-tight engagement within the first cross-sectional shape, the third cross-sectional shape being mismatched with a second cross-sectional shape to form a mismatch zone along a length of a chamber, the mismatch zone allowing fluid flow around the valves, thereby to allow the two valves to effect mixing of the fluid substance with the solid substance and subsequently to remove excess fluid to obtain the resulting substance having the desired consistency.