Pop it in the anal canal, slide your balls into the split-ring ball separator, get yourself all situated and enjoy this sturdy made prostate massager while around the house of just out walking.  The gentle tugging on your ball sack, coupled with the semi-soft plug moving about the anal canal will produce some very erotic sensations.  Although this item is non-cunductive, placing electrodes along the shaft or a loop around the head will simply enhance the experience.  

Notice that the upper "cup" of the ball splitter is ergonomic and should add additional comfort to the user.  You can choose to not split the ball is you desire due to the design.  

Oval insert is 1.6" in diameter and 2.1" long.  8cm = 3" and 3cm = 1.2"