A penile prosthetic (20) includes an inflatable member (24) that is implantable into a penis of a user, a reservoir (22) that is implantable in an abdomen, and a pump (26). The pump is configured to be attached between the inflatable member and the reservoir and is implantable in a scrotum. The pump includes a pump bulb (42) having an internal cavity formed by a side surface connected between a bottom surface and a top surface of the pump bulb. The side surface provides an outside circumference of the pump bulb and includes at least two concave side walls with each concave side wall connected between two adjacent convex lobes of the pump bulb.
