With the latest patch, one’s balls are a valid site for piercings now. With that in mind, piercings like the Opal Ring gotten from Mitzi, should provide their bonus when in the balls slot, since it counts as valid genitals.
Adjusted for the next release. Keep in mind that the piercing check is not additive, so if you have piercings for both the cock and balls, it won't change the bonus values. Having at least one of them pierced should be enough for the bonus towards cum output.
