It usually works better if you are not touching your partner in any way, not even holding hands. Focus on the words and don't let yourself go to sleep. Allow your imagination to come into play. Imagine that you can feel the sensations and see the images that are suggested. Really get into it.
Some people are able to visualize more clearly than others.
Other people get strong feelings without visualizing anything. There is no right or wrong way to do this exercise. Whatever experience you get is right for you. After the exercise, share your experience with your partner. Remember, it is meaningless for you to judge someone else's experience as better or worse than your own.