My now 28yo, ASD3 daughter will still bite at this age, with some caveats.
She has a mental age of 1.5yo and will bite out of anger, anxiety or for sensory reasons. (You can't always see the last one coming.)
When she was about 12, she bit into my arm one day and would not release me. I slapped her thigh just enough to sting. When she cried, she released my arm. When she tried to continue biting me, I gave her a minimal slap to her lips and she backed down. Whenever she tried to bite me after that, I would just raise my hand and she would halt her attack. It was similar for pinching.
Unfortunately, she continued to bite & pinch her teachers (who rejected and were blocked from using such physical tactics) and fellow [special ed.] students. But her bus driver was not afraid to slap pinchy fingers. (We could tell that [the driver] was not being mean.)