Having a haircut
Many autistic children have a hard time getting a haircut. This is a problem. They might get very upset, will not sit still and panic. I think that there are two possibilities.
One option is to slowly get the children get used to the haircut with scissors. Little by little they can have the experience that it is not that terrible, when you take them on your lap every day (at a predictable time) just to have one or two cuts. Immediately after that they will get a reward or a compliment: “Very good, you had a haircut!” This can continue like this, slowly but steadily, until there is no negative reaction anymore and they remain relaxed. Then you can proceed to more cuts. There will be a time when the haircut will be just a usual procedure.
The second option is to cut the hair with the trimmer every two or three months, holding the child steady in your arms and finishing quickly. It may be an act of violence of course, but at least it will be over in no time and the result will last for months.
If you, as the parent, can remain calm and act in a reassuring and decisive manner, showing the child that it is something that will have to take place, he can understand that it might not be so terrible after all. Often our reaction triggers a greater panic than necessary. It does not mean that it is easy for the child, he probably is still afraid, but your calmness also shows your acceptance of his reaction.