WARNING: This is a placeholder site at the very earliest developmental stage
TOUCH CONSENT - TEACHING BOUNDARIES
Safety is always first.
In the interim, as a parent, you take what steps you can or must in order to keep all, your child also, safe, by other means - consequential actions that are effective. That may mean not going somewhere, having one parent 110% focused on intercepting only, being directed to other activities before possible unconsented or harmful touching arises.
Then THEIR consenting.
The concept of consent is best taught by first strongly teaching a child what THEIR rights are, finding out what personal limits THEY can state, showing THEM how to communicate these boundaries and preferences - and only then seeking to extend that to how they are towards others. It is important to consider the wider picture globally also ... autistic children are vastly more likely to experience unwanted unconsented impacts from others than to initiate the same themselves. And where they do initiate, often it stems from the lack of respect shown to them. This is not to excuse autistic acts, merely to situate them more broadly.
"... consent cannot be taught in a context where non-compliance from autistics is systematically eliminated." It needs a solid base to build an understanding of consent. The child in questions understanding of their own rights.
ABA, open or hidden, makes it worse.
Coercive compliance, normalization attempts, i.e. ABA, makes this factor - a child's rights being abused - so much worse for those around the child. As autistics together state (ASAN):
"People with more power than me can force me to do whatever they want... nobody, not even my parents will come to my defence... other people are in charge of my body... I'm not allowed to say 'no', or to protest... it's OK for people to physically move me or grab me if I'm not doing what they want".
Then generalisation, context, categories.
There will likely be much extra work to teach about consent in all situations, new ones that arise also, as some autistics have less ability to generalise a rule across all situations, as they are detail-oriented, dealing with one thing at a time, are context sensitive, have quite a different set of categories from you (e.g. cousins, friends versus 'friends', the elderly).
With some autistics, to avoid them sensing it is all negatives, about "No!", and specifically aimed at limiting them, you may beed to teach a wide range of positive things they can do instead, with role-playing how to ask for a hug, high-five, ask for a sensory option, and also role-playing how to refuse whatever he wishes to avoid himself.
Impulsivity and sensory-seeking are here.
But in the very moment when he touches, sensory-seeking and impulsivity may still be the issue with him. He acts more quickly than he remembers safe alternative sensory opportunities or what he has learned about consent and gow it cuts both ways, improves all lives including his.
Every uncaught-in-time unconsented act can become an opportunity for him to try-out the safe alternative or to ask for permission, in addition to being told to stop, apologise, move away.
Further reading:
Raising Human Beings (2016) contains much help for parents from Dr Greene on this and connected topics - impulsivity, rights, sensory-seeking, etc. Used copies go for $12+p&p. I recommend this book.