This is another piercing done by many tribes and throughout history. This piercing is the transverse of the Apadravia. Unlike the Apadravia it does not have to go through the urethra and needs to be placed back far enough to sit in front of the rim but not so far back to hit the ‘Erectile tissue’ in the penis, the corpus cavernosa run up each side of the penis shaft and fill with blood when the penis becomes erect. If you hit this during piercing then the client will have a lot of bleeding which may eventually stop but will persist for a long time and in worst cases will need medical treatment.
I guess we can safely say that the benefits of this piercing for both partners is why it remains popular. when healed the length of the bar should be sized down to 1mm shorter than the measured erect length of the piercing and so when erect the balls put just a little pressure unto the glans this can be stimulating for the wearer also the erection causes the tissue around the bar to contract and become tight on it so any movement of the bar stimulates from within. As for the partner it gives extra girth an stimulation from the balls on each side. There is one tribe where it was reported that a woman could leave/divorce her husband if he refused to get an Ampalang piercing.