That is also where the sensory receptors usually are located. We can of course ask further why that should be, and I suspect that sensitivity to stimuli may be more basic than the reproductive characteristic despite the view of many modern biologists. It is usually touch which is reacted to by unicellular and primitive organisms, and this continues in higher organisms although with a somewhat different distribution of different senses. Reproduction, on the other hand, takes extremely different forms such as asexual versus sexual. Dancing, however, is essentially tactile.
People nod their heads or tap their feet often in listening to music and even playing music.
Mozart was into waltzes, and his Italian rivals not only danced but moved their arms in conversation quite frequently - they still do. Von Weber's Invitation to the Dance is immortal. Mathematics relates to the tactile sense via geometry. Osher Doctorow Doctorow Consultants, Ventura College, etc.