An applicator for applying a fluid to a surface is provided, the applicator comprising a support comprising an upper outer surface and a lower holding surface; a flexible membrane comprising a central opening, an inner wall comprising a lower end and an upper end, an outer wall at least partially surrounding the upper outer surface of the support, the outer wall comprising a lower end and an upper end, and an upper folded wall connecting the upper ends of the inner wall and outer wall; and a membrane holder for fixedly securing the lower end of the inner wall of the flexible membrane to the upper outer surface of the support; wherein the upper surface of the membrane holder and the inner wall of the flexible membrane define a reservoir for holding a fluid, and wherein the lower end of the outer wall of the flexible membrane is free to move axially relative to the upper outer surface of the support when pressure is applied to the upper folded wall of the flexible membrane. In an embodiment, the applicator has particular utility for applying a topical or transdermal testosterone composition to the skin of a patient in need of testosterone replacement therapy.