Say you were at a funeral, and a family member of the deceased said something unintentionally hilarious as part of a eulogy, but only funny to a very small number of people at the funeral. Obviously, it would be very socially inappropriate to laugh, but are normal (neurotypical) people capable of stopping laughter right off or preventing it from starting, or is it normal to not have complete control over laughing?
Yes, it's possible to control your laughter. There are several methods of controlling your laughter or laughing without anyone being hurt in the process. Such as
Think of something sad and depressing: Although this can be unpleasant, it usually takes care of the uncontrollable urge to laugh. If sadness doesn't work, fear is also extremely effective. Think of a scene from a horror movie you just saw or a car accident. This is physically proven to work because the adrenaline (the fear hormone) released from your brain when you have these thoughts will block out the endorphins (the happiness or laughing hormone). It may take some practice to convince yourself enough of the fear, but once you have mastered it, it's very effective.
Force yourself to turn your laugh into a cry: if the occasion is something sad such as a funeral. Some people sound like they are laughing before they cry.
•If it gets really bad, hold your nose and cover your mouth with that hand. Then people can't see your grin, and you can laugh as hard as you wish inside yourself. You may start shaking, but that's okay, it can be covered as crying. Try not to let any sound out, but if you do ease up by accident, it sounds much like a sneeze or a strange snort.
Pretend to pick your teeth: Open your mouth wide and pretend to pick away at something stuck. Not only does it totally hide your smile, you also clean your teeth at the same time! Be careful though because the face made is funny enough to make others start laughing when they see what you're up to.