Abstract: A condom is described in the form of a generally cylindrical sheath that extends along a central axis having an open end configured to accept a penis and an opposing closed end. On the inside surface of the sheath, one or more annular ribs are provided that extend radially inwardly towards the sheath's longitudinal axis. The ribs are configured to provide a greater hindrance to blood flow within a penis received in the condom in the direction of the open end as opposed to blood flow in the direction of the closed end.

Abstract: A condom that extends along a central axis and has a series of ribs along an internal surface of the condom. The ribs having a concave surface that encounters blood flow from the heart, and thus uses the blood flow to urge the rib away from the central axis. The ribs also include a wall that is positioned so as to encounter the blood flow returning to the heart, the wall being vertical or concave, so as to not urge the rib away from the central axis of the condom.