Anyway, I actually spend a lot of time thinking about effective mantras.
For demonstrative purposes, let's consider the relatively classic mantra 'good toys obey'. Three words is a good length, no especially hard sounds to make, and a relatively fun concept to impose.
Sometimes I feel like in hypnosis smut I see there's this idea that words have innate power. Or like, that a mantra's meaning becomes more self evident upon repetition, but personally I don't really think that's the case. I think that, at least in my experience, most phrases tend to move in the opposite direction, gradually becoming less 'meaningful' and more just noise. Thus, as a hypnotist if you're playing with mantras I think it's your job to fight that.
If you repeat the phrase 'good toys obey' to yourself over and over, I expect you'll notice this effect. The sounds begin to blur together. Maybe you find you've stopped saying it fully out loud and you've started mumbling it under your breath. The words lose their independent meanings, and it becomes just sounds that you're forming with your lips.
Then, from my perspective, to walk through this properly, there's, like, three purposes to the mantra.
First, sensory input. By having your subject repeat a phrase over and over, a part of its brain is going to be automatically following along with what you tell it to do, and further some of its sensory input is going to be filled up by the process. And through this, some part of it is going to be constantly following along with you.
To strengthen this effect, I like to call attention to the feeling of the words in the subject's mouth. Feel how your tongue moves through the syllables. The way it twists and bends and shapes the sound leaving your mouth. Even if you're just whispering, it shapes the air you breathe out. Feel how the air is shaped into meaning. Feel how easy it is to follow along and repeat the mantra. Feel how easy it is for the motion to become a tic, an automatic process, and even then how a part of your brain is locked into thinking through the words. Forming them and noticing their formation.
Second, additional meaning. I like to try to play with the meaning of the words. Remind my subject what it's saying, and what it means for it to say that. I think this occurs passively even without effort, as the rest of the hypnosis is presumably along similar thematic lines, and in the subject's mind it will make these connections. But, ideally I want to be spelling things out. And in that process, I'm asserting a control over the meaning, and a control over the meaning of the subject's actions.
For this effect, with something like 'good toys obey', I want to be breaking the phrase down and connecting it back to the subject as it repeats the mantra. I'll tell the subject that I want it to be a good toy, that is is my toy, that it can be a good toy for me, it just needs to obey. And, clearly, the subject is obeying. It's repeating 'good toys obey' back to me, as I told it to. And, I want to be focusing on this loop. Reminding it that with each repetition, that it's obeying me, and thus proving that it's a good toy, and thus affirming that good toys do obey. I want it reminded of and verifying it's obedience. And, I'll point back and call back to this over and over. Keeping the subject cognizant of this loop.
Third, what do mantras signify? Hypnosis is very interested in what it signifies. I've read a good article that argues that the only shared factor among most hypnosis is being called hypnosis, even as hypnosis clearly exists. It occupies an interesting space here, and thus I want my subject aware of that. I want my subject thinking about the subtext of and implications of it repeating a mantra for me. I want it thinking about how it looks, thinking about what it means, and thinking all these things as I tell it to.
And, to accomplish this with my subject, I'll simply call attention to it. Spell it out. Once it's deepened enough that it's repeating 'good toys obey' over and over without much chance of stopping, I'll remind it of what that means. Tell it it looks like a character in hypnokink smut. Ask it if this is panel 1 or panel 2. Point out how silly it looks repeating such a silly phrase for me. Point out that it's doing this for me. Ask it what it means that it's doing this for me. Make sure it's aware that not only is it being a good toy for me and an obedient toy for me, but that it's looking increasingly like a hypnotized toy for me. I'll call out its body language, point out how its eyes glaze forward or guide them to close, call attention to its relaxed body, tell it how comfortable it looks. And I'll construct the idea that it is hypnotized within its own mind, and thus complete the self fulfilling prophecy.
Anyway, I know this was a lot, but I like mantras a lot. I think they're a fun toy to play with, though I like a great many toys. I try to be mindful with their use, intentional with how I employ them, but I like the effects they have, and I like the space they play in. I like having my subjects repeat motions or follow along doing things I tell them, even when it's silly or easy. I like exploring the construction of hypnosis and looking in the black box to see what we'll find And, I think they're really hot, too.
Plus, it's fun to see if the subject still repeats it or stops immediately after I tell it to wake up.