So much of success in life - in and out of school - is about being able to control emotions. This doesn’t mean repressing emotions, but knowing when it is appropriate to let them show and when to act upon them, and when it is not.
Toddlers often bite, pinch and kick and this is all perfectly normal. But they also need to be shown ways to eventually move away from this kind of behaviour.
Books about tantrums and especially physical behaviours can be a useful way to approach this without directly confronting your child about their behaviour. Puppet play also works well. Punch and Judy shows are rare these days, but the idea of telling off a naughty puppet for his errant behaviour is something all children enjoy doing - even if they are transgressors themselves.