"...then try this one for size." the fairy giggles.
You wake up in time to see the two fairies darting back into the forest, and they are quickly lost to sight.
You sit up, feeling strange. At first, you think nothing has changed, but quickly you realize that, while you're still female, you're not a fairy. You're human sized and no longer have the wings you had a few minutes ago. Your hair is long and blond, hanging down to your breasts, which are so large you think you're going to topple over when you walk.
You stand up and look around. Did the fairies make you human again, even if you're no longer male? You're not happy about that, but at least you can return home.
Walking out of the ring of mushrooms, you're surprised that your bare feet don't even register any discomfort walking across the forest floor. It's like you're walking on air. The wind though the trees make you feel... wonderful.
It's not long before you stop to rest against an old oak tree. You sit down, mindless of your nakedness, and run your fingers though the soil. It feel good, right to your soul. Your start to feel the old tree root, and you instantly feel a connection.
You pull your hand away, suddenly scared. The faries changed you, but not into a human. You're not sure what you are yet, though.
Your hand touches the bark further up the trunk, and then presses into the tree. It feels safe, like you're home. With a moments thought, you step into the solid trunk like it's air, and instantly you bond with the oak.
Inside, your senses infuse the tree. You're aware of your surroundings and you draw life from them. You spend days, maybe weeks, resting from your transformation, before you even realize that they've passed. Once rested, you find yourself able to step away and in time to discover what you can do as the newest wood nymph of the forest.