The very rare time hes force to shift into feral is when his dragon side overwhelm him or lose control from burst of certain emotions. Kind of an allusion that not being his demi form represent the “absence” of humanity. He doesn’t remember when those moments happen, describing the feeling like blurry with wild in and out moment of lucidity. Being only half dragon he is not used to the sudden urge of primal instincts of a pure blood one, which just end up taking control until he can reverse back.