All this key item does is reduce the speed at which your ejaculation meter fills, but it doesn't make sex any more stamina efficient. On top of that, it can't be turned off... once you buy it, it's always active.

Since achievements in this game ask you to ejaculate as much as possible, this slows down achievement progress while giving zero perks and numerous drawbacks. If it had the opposite effect (speed up the ejaculation meter), then it would be a much more useful item. Currently, this is an item that should never be purchased, and I wish there was a way to get rid of it once you do make the mistake in buying it.

Most of the other key items are pretty useful, but this one is actively, irreversibly harmful.