Slavery: A series of erotic games (book 04)
"Why doesn't your Master use it to make you do things like that?"
"He won't use it to exceed a hard limit. Perhaps he'll stretch a soft limit with it, but never a hard. He used it to make me swallow his cum when I started my slavery. It wasn't a hard limit. I'd swallow on his birthday, or our anniversary, but I didn't like it. It was never the taste which disgusted me, but the texture of cum. He used the Slave Trainer to get me swallowing every time. The only way I was allowed to cum is if I swallowed his. Now, I love to swallow cum, not just his, but anyone's. I enjoy the hot, salty splash of cum in my mouth. If you don't want to swallow, you'd never make it as a sex slave."