Technically it seems like the key factor is to improve blood circulation down there to promote vascular growth. Wonder if someone could replicate the expensive machine using a piezoelectric disc driven by frequency generator to create and control the vibrations.
... When cannot stand, complain cannot stand. When can stand, complain cum too fast, when that is solved, complain it's too small, and when even all that is solved, complain sperm count low and impotent
Plenty of opportunity for medical science!