I used to cut my boys hair when there when little, as they got older, I never could line there hair right. After, two barbers I found one that was very sympathetic and accommodating. We go on a specific day and time and sometimes one of my son's helps with the prep and clean up. Its been 5 yrs.now. it's been challenging and we have to tweet but that comes with the territory. This is no different when looking for a doctor or therapist, as you continue to take them they will get use to going and come formular.
I don't know if you have any these in your area but we took our boys to a kids only salon. They had cartoons on and toys to play with but the best things were that the stylists were used to working with kids who do all kinds of unpredictable things and when kids freak out its pretty much expected in those places and nobody gives you the stink eye. There was even a gal at our salon who was super patient and has a lot if asd clients. She wasn't extremely educated in asd but she was incredibly kind and went with the flow when things got challenging.
We had my son's school do a desensitization program. We also found an excellent barber.
i give my son my phone ..and he sees youtube...when they get his hair cut ...works everytime ! :)
Keep going to different barbers until you find one that will talk to your child... ignore your child.. whatever is needed. The barber is a big thing for my ds... loves to go with DAD! They used to go to a old fashioned barber that would use a massager after on the shoulders... funny!! PS... I never felt bad for the lady that cut her hand because my ds was moving. She didn't want him there and should have been more open with me before he sat in the chair and started barking that he needed to sit still. And she cut like she was in the biggest hurry. By the way... my ds doesn't move anymore in the chair... he is 10.