Poké Ride is a feature that lets you ride Pokémon in certain places normal travel can't do. You can soar on Charizard, find hidden treasures with Stoutland, fish with a gentle Lapras and much more! However, unlike in previous generations, you can access this any time you want, and don't need the Pokémon with those HM's to do so. Most of these ride pokemon are rideable by pressing Y then B.