Slavery: A series of erotic games (book 01)
Then I stopped, while she groaned in disappointment.
I got down so I could speak to her face. "Somehow, slave, you seem to think you can cum every time you want. This is a terrible quality in a slave. She should be concentrating on her owner's pleasure, not her own. Perhaps I've been too lenient with you, let you cum too often. Perhaps you need more work with the Slave Trainer; leave it on you for a day."
"Master, I don't believe the Slave Trainer's purpose is to train a slave not to cum. It won't allow me to cum, but it leaves me on the edge where the slightest stimulation releases me. I suspect it makes me more orgasmic, not less so."