Aella offers some suggestions on her website knowingless.com. 

This is written mostly for higher doses of acid, usually 200ug+, where a tripsitter may become seriously needed. This is all written with the assumption that you’ll be indoors, which is strongly recommended unless the person tripping has a lot of experience with the dose they’re taking.

1. Don’t try to interact with them too much.
Tripping people are closer to children. You won’t be able to communicate any normal adult things with them, they won’t always understand the questions you ask, and the experience they’re having is so different from yours that trying to talk to them will be more trouble than it’s worth. The amount of mental effort they need to put into understanding what you’re saying will be more distracting than useful.

2. Your role is parental.
You’re there to serve as a buffer between them and the scary world around them. Answer the door, take their phone, give them coloring books and glasses of water. Asking what they want usually won’t help and will be distracting – instead of asking them if they want water, or to hold your hand, just give them a glass of water and see if they refuse, or take their hand and watch how they react.

3. Reassurance

If they ask what’s going on, tell them, literally and exactly: “You took some acid about 3 hours ago, and we just got back from the walk. Now you’re in my house and we’re sitting on the couch.” You may need to tell them what’s going on repeatedly, but even with repeated questioning they usually still want the same literal answer, over and over again. If they insist that something is going on that isn’t, for example “I need to give you this object so you can go back in time,” don’t tell them they’re wrong. Play along. They will probably forget what they’re doing soon. They might be insisting on something false that is causing them a lot of discomfort, such as “my family hates me.” Don’t tell them they’re wrong, just listen. If it’s getting serious, you can try to redirect them, but don’t push back directly. For example, “your family doesn’t hate you” is not very good, but “your family took you out to dinner and hugged you last week” is better.

4. Language
Use very simple words and short sentences. Speak slowly and clearly. When tripsitting I talk to them the exact same as I do to children. They may be experiencing auditory hallucinations, and so will have trouble hearing what you’re saying. Their attention span will almost definitely be shortened, so they won’t be able to follow along complex concepts that require multiple points of data. More ideally, communicate with them physically, by demonstrating things with your body, using your face, pointing or laughing, or even drawing.

5. When not to comfort
Don’t ask them if they’re okay. You want to allow them to process things without worrying that they’re distressing you, so don’t act distressed or like you’re trying to fix the situation. Allow them to suffer if they need to. If they’re in pain, or sobbing, don’t say anything. Hug them if you think they might want that, or put a hand on their back. If a sad song is on and they’re obviously affected by it, don’t stop the song unless they ask for it (rather make sure a more happy song plays next, if you think that’s what they want; keep in mind they may want deliberately painful songs.)

6. When to comfort
If they’re experiencing fear, this is the time to comfort. They trust you (hopefully), and their ability to read minute body language is probably heightened, so make very sure that your body language remains calm and your smile gentle, even if you are stressed or worried. This is maybe the most important thing, to act as a stable and calm center for them to use to reassure themselves. No matter what, never allow them to see concern, even if you are actually concerned. But again, be careful of directly contradicting things they say. Redirect, don’t tell them they’re wrong. Don’t try to debunk any delusions they might develop.

7. Loops
Sometimes people get caught in loops, typically between 5-60 seconds, where they will repeat the same series of phrases or ideas over and over again. This is usually easy to handle – if they’re upset, they’ll forget in a few seconds, which means they’ll have trouble actually acting out on being upset. Figure out the things to say to reassure them. I recently tripsat someone who thought his hand was bleeding, and every 30-60 seconds he would say ‘am I bleeding?’, and every 30-60 seconds I told him he wasn’t bleeding. This went on for hours.

8. Mania
Some people, on high doses, lose contact with reality and become loud, aggressive, or just generally super physically active. This is really annoying to handle, because it’s extremely difficult to get these people to take vallium or whatever helps them calm down, and so usually you just have to ride it out. Never tripsit someone who is bigger than you, if you are alone. Be prepared to call a friend to help deal with them. Sitting on someone at this point to prevent physical damage is generally not troubling to the person tripping, as they’re probably going to experience memory loss and aren’t really that aware that you’re sitting on them, even if they say things like ‘get off.’ Thought loops at this point usually tend to be 5-10 seconds long.

9. Paranoia
They might not trust you, or think you’re from the CIA or something. This particularly pops up when you’re in charge of their belongings, such as their phone or keys. This is very difficult to deal with. If the paranoia gets to the mania stage, just sit on them and then you’re good. If they’re not manic, be sure to act very calm, not very defensive, and as gentle as possible. Your goal here is not to eliminate their paranoia, but to keep them calm until it ends. A possible technique here is to ask them questions about what they’re paranoid about – if they accuse you of being in the CIA, try to gently ask them what it means to be in the CIA, why they think that, and followup questions about whatever they are saying. Getting them to express their opinions is a good distraction.

10. Timing

You want to wait to see how intense a trip will be before taking them outside, and for this I generally recommend waiting 3-4 hours, assuming by that point they aren’t showing any signs of increasing the trip. I have seen trips get more intense after this point, though this is rare. You should start to see a comedown around 5-6 hours, though this can occasionally last as long as 8-9 hours.

11. Don’t fuck with them

Seriously, this is one of the cruelest things you can do. If you don’t understand why you shouldn’t, you need to take a high dose of acid. If you wouldn’t do it to a 4-year-old, don’t do it to the vulnerable person trusting you to care for them.

12. Beneficial tricks
These are mostly to use for anxiety or fear, not for sadness (you should not try to stop sadness!). Scenery change (from one room to the other, lights on or off, or music changing) can be extremely effective. If they’re of a state of mind to follow instructions, try to have them sit cross legged with their back straight, and guide them in deep breaths. Mostly demonstrate this in front of them and gently encourage them to follow, but don’t worry or say anything if they just start rolling around or something.

13. Body quirks
Acid is extremely safe. People may experience temperature fluctuations, numbness, limb shaking, jitteriness, fast heart rate, nausea, or headaches. This is normal (unless they’re symptoms of an unrelated condition that happens to be striking at the same time). Be prepared to reassure them for any weird things their body does. The only real danger is environmental damage (if they run into a glass table, for example).