In his seminal 1981 study of the sport, “The Soccer Tribe,” the zoologist Desmond Morris included the gesture in his catalog of 12 player reactions to defeat. He noted its function of self-comfort, which he described as “a form of auto-contact, a widespread device used when the individual feels in need of a reassuring embrace, but has no one immediately available to offer one.” It’s seen among nonhuman primates as well.