Getting a man to accept sexual slavery is easier in a new and uncommitted relationship than in an established and committed one. When the relationship is new, he's turned on to you, concerned about pleasing you, probably in love with you.
You don't have to overcome established patterns of interaction that are inconsistent with female domination, and he's encouraged by the thought that if the experiment goes badly, he can cut his losses and flee. On the downside, there's a much greater risk that the mere attempt will scare him away for good.
In a committed relationship, you'll have to work harder to enslave your partner and there's a greater probability that you'll fail, but the chance that the attempt will end the relationship is slim. In an uncommitted relationship, the least likely of the three possible outcomes is that he'll refuse to become your love slave but remain willing to negotiate some other arrangement.
I enslaved all my lovers early. Since I wasn't interested in any other sort.of relationship, I didn't worry about scaring them off. Only two ran, but don't let that encourage you more than it should. Remember, anyone can see before getting involved with me that I'm a tease. Remember too that I'm rarely attracted to a man unless my intuition tells me he's well suited to my agenda.
If the same number of partners had been assigned to me at random, I'm sure at least three would have run. What I'm getting at is that my advice is based on the assumption that you're not worried about losing your man. If you are, be forewarned that I haven't taken that into account. You may lose him. Use your priorities, not mine, in deciding whether to accept the risk.
The way I invited Patrick to become my love slave is just one possibility among many. You would likely set up a different scenario. It's exact nature would depend on your age and experience, your partner's age and experience, quirks of your personality and his, the degree to which you're worried about venereal infection, and so on. We'll look here at some of the possibilities - not all, by any means, but a few that seem generally useful.
I'll proceed from the assumption that you're truly determined to enslave your man. This will permit me the corollary assumption that you're willing to wield the one threat that underlies all female domination: Your man can't have you except on your terms. You have to be willing to make that a rule, make it clear, and enforce it. If he won't do as you say, put some distance between you and leave him sexually frustrated, accepting your own unsatisfied lust as an unfortunate necessity.