MC dies from masturbating too hard and reincarnates into the VR eroge he was playing. He is Sao Jisansuke, an old man sao character whose purpose is to NTR the protagonist. Whenever lewd things are about to happen, he will always turn into an old man. To fix this bug, he must collect the magic rings that the heroines (perverts) possess.

Sao: a role that serves little purpose outside of erotic events.