Negotiation
Before you hypnotize or are hypnotized, you need to trust your partner to know what you want, and what they want, and have worked out your expectations.
For example, your partner may be turned off by hypnosis, but interested by guided meditation or ASMR which are related to hypnotism, but do not have the cultural connotations.
Sit down with your partner and talk things out. This is about your general framework about hypnosis, rather than what you’re going to do in an individual session. You should have an idea of when and where you’re doing this, how often, and what your parameters are.
You need to negotiate consent, establish limits, and determine aftercare.
Consent
Negotiating consent is a framework for establishing agreed on behavior in a hypnosis session. Here are some consent phrases you can practice.
At the same time, beginners can’t ask the right consent questions and may not know what to expect. You don’t know what is okay for you and what isn’t if you’ve never experienced it. This is another reason to go slow, get lots of feedback, and be clear that it’s okay to stop or pause if you’re uncomfortable. Here’s a sample list showing things you can talk about. Here’s a NSFW list.
There may be specific issues that could come up that have unexpected connotations. Your partner could have a phobia of spiders, or may react badly to sudden noises. Go over things that you should avoid in sessions.
Safeties
You should go over a prearranged safety system with your partner. This can be whatever you both are comfortable with: some people use a "traffic light" system to mean "stop, uncomfortable, happy" where your partner can always say those words at any time, while others use a TTRPG safety toolkit. HypnoticHarlequin has a nice guide to nonverbal safewords.
I personally like to set up a hand signal system. The advantage is that hand signals work even when your partner is feeling non-verbal, or is in deep trance, or doesn’t want to interrupt you.
Tapping out is a sign that the session needs to be put on hold, and can be done by tapping the hand against something repeatedly. This can be used for bio breaks, nervous energy, or if your partner isn’t comfortable with a suggestion or is feeling dysregulated.
Raise hand is a sign that your partner would like you to check in with them, or would like to provide feedback on a suggestion. Your partnet may want to let you know that your tempo is too fast or slow, or that they need more active suggestions, or that they fully understand the suggestion, are completely ready, and would like you to explaining it.
Thumbs up is a sign that you are enjoying and are happy with the suggestion and have no issues. This can be useful when your partner may look uncomfortable or in distress, but is actually fine.
Go over it with them, and have them practice it a couple of times to make sure you have the same understanding of what their use looks like.
Limits
Keep an open mind, and be aware that hypnosis may be an unfamiliar activity. By setting boundaries early and starting at the shallow end of the pool, you can build up experience and trust.
There may be some things that your partner does not want to do and will never want to do. Know your partner’s limits.
Aftercare
Aftercare is very individual, and depends on your relationship with your partner. Some people want to be held, other people need time to themselves to collect their thoughts, and some people want positive statements and reassurances. You should negotiate what kind of aftercare your partner will want.