Caring for and forming a bond with your pokemon takes more than just throwing them into battle at every opportunity. They require food, attention, and love. Often times the also require help with certain things they couldn't do on their own in the wild. This varies from species to species of course. In the case of Wooloo's however, when the weather gets to warm and stifling for their thick wooly coats, shearing some of it off for them is a great way to give them relief, as well as a way to bond with them. You'll know your Wooloo trusts you implicitly when they come to you to shear them. Just don't get any other uncouth ideas in the process, no matter how much she may appear to plead for it.