Preheat oven to 350 degrees. Line a baking sheet with parchment paper and set aside. In a large bowl, mix oats, bananas, peanut butter and coconut oil. Keep adding oats as needed until dough is no longer sticky. On a lightly floured surface, knead dough 3-4 times until it comes together. Roll to ¼ inch thickness and use cookie cutters to cut desired shapes. Place on baking sheet and bake until edges are golden brown (about 10-12 minutes). Let cool and dig in with your dog!