A male external incontinence device comprising a drainage tube assembly having a proximal chamber in fluid communication with a drainage tube, the proximal chamber comprising an atmospheric equilibrium valve assembly. The atmospheric equilibrium valve assembly has an airway conduit with a upper portion in fluid communication with the proximal chamber, and a lower portion having an air inlet chamber. A one-way air valve disposed in the airway conduit above the air inlet chamber, the one-way air valve comprising a first pair of opposing walls disposed at a first set of opposing angles such that the first pair of opposing walls abut each other at an apex, the apex having a self-sealing slit.