"I'm ready." You said, plain and simple.
The fairy smiled and she started flying around you, trailing an ever lengthening streak of light behind her, lifting your body into the air. The trails of light remain as the fairy breaks off, and she begins reciting: "Let my magic wake your own; change you down into your bone. Bring the truth of your own soul; to the surface with a pull. Be reborn that here you dwell; once concluded is this spell."
The moment the last word was uttered, your clothing shredded apart and you felt a tremendous pressure at every point on your body, as if it were being compressed. Other sensations joined in; your face felt as if it were being smoothed out and your eyes were expanding a little. Your ears felt like they were being pulled and stretched as they grew longer and pointed. Your hair grew to where it might fall slightly past your shoulders were the effects of the spell not creating a weird anti-gravity effect. Your shoulders pushed closer together as your arms lost muscle and your hands became slim.
You couldn't see these changes for yourself, due to the sensory overload causing you to squint your eyes, but there was no mistaking a swelling on your chest, you were growing breasts. From the duration, they didn't seem like they were going to be quite a c-cup, but they were firm and supple. As your waist pinched in and your hips flared out, you began to savor the bizarre mix of pain and pleasure; which only intensified once the change targeted your manhood, shrinking them away, and swallowing them into a pink slit between your legs. Your bodyhair was long gone, once your legs started losing muscle tone and bowing out into a feminine curve, with your feet growing slender.
The pressure gave way to a pleasant tingling sensation as your skin developed a soft, radiant, glow with a gentle sparkle. Just as you let your guard down, the pressure returned on your back with a vengeance; but this time it was from the inside out. You lurch forward as two bulges form on your back which soon break open, releasing two, crystalline stalks each that grow and expand into four broad, flat sheets of clear, sparkling material with intricate patterns branching off from the main base.
The magical ribbons holding you up dissipated and, on instinct, you catch the air by beating your wings. You looked behind your back at the buzzing, ringing new additions to your back and gasp heavily. "I'm a... FAIRY!?" You then look back at the fairy who cast the spell, now staring at you with a gentle blush. "Y-you said... I didn't have to..."
It took a brief moment for the fairy to break her trance when she finally spoke up. "Oh, uh... what I said was you will become what your soul desires to become... and, by sheer coincidence, it just happened to be a fairy."
"But why did I become a FEMALE fairy!?"
"Because all fairies are female. I guess you didn't know that."
You look over your body. It didn't look half bad; certainly a body you'd be attracted to, and still are, in fact. When you looked back, the fairy was gone. You look around to find her pulling petals off some night blooming flowers and working with them on a tree stump. You landed behind her in time for her to present a set of clothes for you; a short-skirted, strapless dress made of flower petals. "Um... for you. I figured you wouldn't want to be naked."
"Th-thank you." You graciously accept the dress and slip it on. It fits perfectly; snug, but not too tight. "It's very nice."
The fairy smiled at you before saying "Lillacia."
"What?"
"My name. You asked what it was before, and since you're a fairy like me, I can finally say it to you."
"It's very pretty." You want to give her your name, but the one you went by as a human seemed unfitting to you now. You had to close your eyes and think about it for a moment. Finally, you said "Call me... Dandelina."
"It fits you." She said.
"Thanks." You answer.