The purpose of sexual play is not merely the utilitarian function of reproducing the species, as it seems to be among animals to a very large extent. What peculiarly distinguishes human sexuality is that it brings the partners closer and closer to each other in an intense state of united feeling. In other words, it is a sacrament, the outward and visible sign of an inward and spiritual grace, that brings about love.
— Alan Watts, Myth and Religion