Just some old fashioned but newly patented physics. The result is LEVITRON™ and ERECTEX™.
Both of these inexpensive medical products are safe and require no prescription. They use natural air pressure, focused and directed on to the penis, to cause a gentle compression, so as to make and keep the penis hard enough for intercourse. There are no side effects whatsoever.
In fact, ERECTEX™, is designed to function regardless of the quality of the erection, and allows a man to achieve penetration without producing any erection at all.