Have you ever seen a horse in the paddock bend in half to scratch its hip?
Its important to remember when teaching your horse lateral flexion we are not building their muscles or working on their ability to flex, they can do this already. We are simply training our horse to respond to our feel and timing through our hands.
I see a lot of people with horses being stiff or stubborn to their hands, if you have a horse being dull to your hands, try flex your horse with a confident hand then release as soon as you get the lightest response, repeat and then build on it.
To clarify what I mean by a ‘confident hand’, is to pick up on the lead rope slowly and confidently to get the initial response, like you are expecting the exercise to go perfectly and he will be light and supple to your hands. Don’t bump just hold. Your horse will eventually soften to your feel and relax into the exercise, it’ll become second nature to you both.
Your feel and timing will develop with practice, take your time.
All the best.