Men, by and large, are warm creatures. Even in the dead of winter, their bodies radiate heat.
Women, on the other hand, are generally cold. Even in the throes of summer, their bodies remain cool.
Neither men nor women realise this fact until they lay beside one another skin to skin. The woman presses her icy fingers against him in the hope of warming them a bit, and the man squeals and squirms like a child trying to escape the spit-dampened thumb of his mother. At which point the woman cackles and places her similarly icy toes against his legs, from which he again retreats, and so it becomes a chase.
But after a while the man learns to expect it, and really, he wants her to be comfortably warm, especially if it means helping him cool down a bit in the process (even if the method employed is somewhat sudden). She still tries to surprise him with her glacial digits, and he, if he is an intelligent being, still gives her her desired reaction before settling in to average their degrees. And if he is very smart about it indeed, he can pull her entirely against him and warm her all at once, which gifts him not only with a more reasonable body temperature but also with the simple pleasure of having such a soft, cool personage lying against him, and, in the rare case that he may be what is considered a lucky man, roaming privileges as well.
Of course, George being the wizard that he is, he could simply cast a cooling charm on himself, or a warming charm on her, or summon another blanket from the linen closet where there are stacks and stacks of them specifically for the purpose of keeping her warm. But our George is wise enough to realise that it's not about blankets and charms, it's not about warm and cool; it's about men and women, and their comfort extends much beyond the heat of their bodies.