Performed on the halfway tumescent penis, jelqing is a manual manipulation of simultaneous squeezing and stroking the shaft from base to corona . Also called "milking",  the technique has ancient Arab origins.  Despite many anecdotal reports of success, medical evidence is absent.  Journalists have dismissed the method as biologically implausible,  or even impossible, albeit unlikely to seriously damage the penis.  Still, if done excessively or harshly, jelqing could conceivably cause ruptures, scarring, disfigurement, and desensitization.