(from a female friend) Go out under a full moon, wearing a special garment which might be considered seductive but not slutty, and carrying another. Remove the garment, dedicating it to the service of some feminist deity. Annoint it with menstrual blood, or with the blood of a cat (animal lovers note....this is how she told it, and I do remember losing one of the farm cats to "coyotes" just before one of the workers began complaining of
impotence. IMO, the former method would be much easier and get you into a lot less trouble, aside from the fact that you might be a cat lover like me and not wish to squish some poor cat or cut its paw. Besides, you're likely to be in some deep doo-doo if anyone finds out. You were warned), making the sign of Saturn at the point where it touches your lower spine. Don your other garment and go home. Leave the annointed garment under his bed.
Go deer hunting, and kill a buck with antlers. Take its blood, and annoint your head with it. Take one of the antler ends, and engrave your name and a sigil of virility thereupon, carrying it on your belt or keys. The farm worker (mentioned above) who received this cure said it worked wonders, and he still speaks of the hunt to this day.