Incidentally the absence of such explanations is what makes so many written accounts of hypnotic inductions disappointingly uninformative. If the subject objects strongly this induction should not be used.
Questions are an excellent way of getting it.
In addition it forces the subject to look up at you. This places the neck and eyes in a condition of mild strain which in a little while will induce a strong desire to drop the head and close the eyes. Ask a few questions about the subject's favourite animal. You are simply establishing the pattern noted above and working to establish rapport. A thing that always fascinates me is the way in which so many animals carry their young.