Hugging a pony must feel great. At least if they take care of their hygiene, otherwise their fur would probably smell and feel bad but most ponies will be bathing regularly. Their fur would be really soft and probably smell good too and then their bodies would be more firm and warm. With them walking on four legs most of the time, their front legs they use for hugging would also be stronger than most human arms so you'd really feel it when they hug you.