The goal is to make the brain reorganize its priority queue so that it quits devoting too much attention to whatever it's looping through and returns to an awareness of ordinary surroundings. People tend to respond best to their dominant sense, so if you know theirs, then choose a method based on that. Ideally, you want a range of options from mild to more intense. The lower levels can produce a smooth return, the middle ones can be jarring, and the upper levels tend to be painful and/or alarming. For example:
* First remove any aversive stimuli, as some people dissociate to avoid stress or have a brain that jams due to overwhelming input. Stop any stressful conversations, turn off loud music, dim bright lights, etc. Create a calm, safe environment. (Special thanks to alatefeline for putting this bottom rung on the ladder.)
* Wait a minute or few to see if it fades naturally. Most episodes are brief, and letting them run their course is the least risky response. Just watch to make sure nobody gets hurt and nothing gets dropped or knocked over.
* Make a little noise, like snapping fingers or clapping hands.
* Call the person's name. People have a learned reflex to respond to familiar modes of address. You may need to try this several times to get a response.
* A code phrase can also be wired in as a learned reflex. Establishing a "wake-up call" can be very useful in circles where someone is prone to drifting, so that friends and family can call them back.
* Wave a hand past their face. The brain detects motion as part of the danger sense, making it harder to ignore than a static environment.
* Touch gently in an ordinary way, like stroking their arm or bumping shoulders. For people who find skin contact triggering or otherwise troublesome, tugging on clothes is safer.
* Blink the lights off and on. The brain is hardwired to detect changes in ambient light, and that hooks into the danger sense.
* Shout at them. If one can use any kind of Command Voice, this is even more effective.
* Some touches are very distracting and annoying without being painful. Shaking briskly, blowing on someone's face, stroking their lips, flicking facial hair or eyelashes, alternating warm/cold, etc. can all work. Avoid shaking small children and anyone with a brain condition or recent injuries.
* A strong new smell such as coffee or bacon can work. Actual smelling salts are pretty harsh.
* Painful touch will rouse most people from most types of fugue state. This includes things like pinching or slapping; try to avoid anything that will cause damage. Dragging knuckles down the sternum is a little gentler, but can be triggering for women due to proximity with breasts, and pain in general is triggering for many vulnerable people. Others will hit back. With a potentially violent victim, consider tossing soft objects from a safe distance. Their response depends on how life experience has wired their danger sense. Another problem is that this method is the one most prone to leaving marks.
* Drop the person a short distance onto a padded surface. The brain has a lot of attention hardwired into maintaining gyroscopic stability, so that kind of vestibular input is compelling. It can also panic people. A further disadvantage of this method compared with others is that bodies are weird, and occasionally injuries can happen even falling a few inches onto something soft.
* Douse the person with cold water. This activates areas of the brain concerned with avoiding heat loss and drowning. A drawback of this method compared to others is that in addition to being very harsh, it can't be stopped instantly when they wake up. You have to dry them off, which usually means undressing and redressing, and by then they can be chilled and shocky.
* If mystical means are available, they have their own scale, and it usually starts in the middle because contacting someone's energy tends to be intimate. Some individuals and cultures are much more casual about this, and established contacts are usually safe too, but with strangers it's a lot more intrusive. In an emergency, modesty goes out the window, but that doesn't typically happen until someone is in clear danger and milder measures haven't worked. If you wouldn't take their clothes off or touch their bathing suit areas, mystical contact probably isn't justifiable either. That said, moving power around someone is less intimate than touching the surface, which is less intrusive than reaching inside their energy field. Among the most useful and least obnoxious is simply bumping energy fields together, which is the mystical equivalent of a shoulder nudge. Mystical people who hang out together and know that someone tends to zone will usually try that first. Some powers lend themselves well to trailing over the skin. Others like Telepathy, Empathy, or Soul Powers can reach inside and 'ring a doorbell' without having to go through the senses. They can also make someone wake up. That's risky for a lot of reasons, but sometimes less so than doing nothing.
These are basic techniques of awareness first aid which prove useful in many situations. Start at the mild end of the list and work through it from there. Before switching from mild to moderate techniques, or moderate to intense, ask yourself if the person really needs to snap out of it or can just be left alone to come around naturally. Also consider the context and the individual. In a crisis situation, upset people are very prone to zoning and jarring them is very bad, so stick with milder levels. Some people may know a specific thing they respond to, or that they need more intense stimulation, or certain things are bad for them. Furthermore, the many causes have very similar symptoms, while unique symptoms are rare; and methods that work great for resolving one type of fugue may make another worse. This is particularly challenging when a single person is prone to drifting in multiple ways. Know the parameters for your friends/family and be cautious with strangers.
Furthermore, understand that fugue states can be a positive, neutral, or negative coping mechanism depending on the cause and the person. If it's you or someone you know, conversation when clear-headed should cover this point and the desired response. Positive fugues should be waited out if at all possible, and that's often a good idea with neutral ones or in an unsecure environment. Negative fugues are better off interrupted more often than not. Also, state of consciousness does not correlate 100% with ordinary responses, and fugues can range from shallow to deep to completely disconnected. Someone who is apparently non-responsive may in fact be aware of you and working as hard as they can to maintain an even keel and be able to stay in touch with the world while handling way-too-intense sensations and/or emotions. In this case, startling them and/or enforcing physical proximity may make things worse by raising the amount of unbearable input they are experiencing. Even if you get a reaction, it may be a flip into meltdown with possible physical and/or mental harm to self/others in place of being "frozen," or a dissociation trip may go "further away." This is why it's important to start at the lowest level of intervention. (Special thanks to alatefeline for adding this.)
If mild measures wake someone up, don't worry, it's probably not serious. If moderate or higher measures are required, and/or the person zones frequently, that can be a warning sign of fugues strong enough to pose a health risk. Discuss whether to activate a WRAP plan or other safety measures if this is more than an occasional event. People who have gone far enough from their body that they don't respond to extreme measures may be in serious trouble. Consider summoning professional help if it is available.
If you have to jostle someone out of a zone, then be prepared to provide aftercare. Coming back abruptly can be a jarring experience, even if it is usually preferable to the alternatives. It may be similar to waking from a nightmare, in terms of the disorientation. The same tips for grounding and comforting that apply to flashbacks or panic attacks often help after fugue states too.