1. (Optional:) Draw or imagine yourself with your desired wolf ears, tail, claws, sharp teeth, etc. If you choose to imagine yourself with the wolf parts, do that as you say the spell. If you choose to draw yourself with the wolf parts, hold the drawing as you say the spell.
2. Say this three times: "Universe, please listen to me. Give me claws and sharp teeth. I would also like to have a (color) wolf tail and my human ears change to (color) wolf ears and these changes shall come even if it takes years. These new parts shall show and hide themselves whenever I please, so let it be."
This spell is from User263752 from SpellsofMagic.