Honestly I stroke down the back of all my snakes everytime I handle them and they seem to be ok with it. Touching most snakes on the head will make them jump and go away from your touch (except my normal who allows me to touch his head because I helped him once with stuck shed and I guess he just knows Im not gonna hurt him). Many people will say something or other stresses a snake out when there is no actual signs of it and sometimes if I get many different opinions I start fact checking away from the forums and hope to find scientific facts.