I think you're referring to something that's commonly referred to as "Tri-mix" and only requires one shot. It is a cocktail(pun intended perhaps) of ingredients, including PGE, PP HCl. All of these are done with a very small gauge needle (28,30) and put directly into the side of the penis, thus stimulating the corpus cavernosa to fill with blood through vasodilation, thus eliciting an artificial erection without stimulus. Priapism is a relaistic problem (extended erection) if too much is taken, but is generally only associated with isolated Papaverine HCl, where the dosage tolerances are very tight. Muse is another option, which is a small, dissolving pellet that is inserted into the urethra, and accomplishes the same thing as the shots, but without the needle, because it simply absorbs across the membrane into the corpus cavernosa. By the way, there is neglible bleeding with the shots so all sexual options remain, but the usual safety practices should still be employed, especially if it's with a new partner.