Prep the skin with antiseptic solution at the planned injection sites. Each dorsal nerve runs just superior to the corpus cavernosum on each side. The corresponding injection sites are at 10:00 and 2:00 at the base of the shaft of the penis. Using lidocaine or bupivacaine without epinephrine, inject 1-2 mL of local anesthetic. Always aspirate before you inject. Repeat the same procedure on the other side.
This technique can sometimes leave the ventral side of the penis unanesthetized. A variation on this technique is to do a ring block. During the injection, instead of removing the need tip completely, advance it caudally to the superficial fascia, aspirate, and then inject as you withdraw. This may provide more effective circumferential anesthesia to the penis.