My previously non-verbal autistic DS aged 3.5 has started to give these commands.
Mummy milk is the only motivator for him. He hates 99% of all known foods including treats and sweets.
I have heard about nursing manners but I fear that it is for much younger children. The "twiddling" command has arisen from me trying to say, "you can have Mummy milk but NO TWIDDLING" 
Sadly it has all gone to pot because we have been hit by a D&V virus and all he could keep down was BM. No milk, no water, no food. So of course I wasn't too fussed about the twiddling. Now he expects it!
DH suggests plasters or mustard 
Any other ideas?