Abstract: An interface plate for a vacuum constriction device used with an elastic constriction ring includes an interface plate member. The interface plate member has an inner cylindrical wall with an open, circular end. The end intersects a planar backup surface perpendicular to the inner wall, such that the end defines a circular aperture in the backup surface. The circular aperture is of selected dimension to prevent the formation of undesired abdominal and/or scrotal bulges past an elastic constriction ring when vacuum is applied to the vacuum constriction device.