The RodeoH harness is about as comfortable as a harness can be. They feel and look like a pair of underwear and come with a storage pouch. For sizing, measure your waist (see photo for size chart). Made of 95% cotton and 5% spandex. Machine wash and hang dry to help them last as long as possible. The designers suggest optimal toy dimensions to be 5"-6" length by 1 1/2"-2" width.