"I know how much you wish you were a girl," she says softly. "And I want to help you. With my magic, I can turn your body from male to female and make everyone think of you as a girl. Do you want that?"
For a second, you don't believe her, but looking at her expression you can tell she's telling the truth. Not only about her powers, but about your feelings- you've never told anyone, but you do wish really bad that you were a girl.
You nod, and she smiles, "In that case, take your clothes off. You won't need to wear boy's clothes again when I'm done!"
Eagerly, you do as she asks. You pull your shoes and socks off, throw off your jumper and shirt, unzip your pants and step out of them, and remove your boxers. Blushing, you lie naked on the bed, and see her withdraw a bottle containing a strange pink powder which she brings up to you.
Rubbing her hands in it, she starts to spread it all over your body- onto your cheeks and neck, then across your shoulders, down both your arms and hands, around your chest (giving you a weird tingly sensation), down along your torso and over your stomach, over your testicles and penis (which instantly turns erect and excited), over your butt and hips, and down your legs and toes.
You feel like you've had a really intense massage. Your whole body is tender and your skin feels so soft and sensitive. "What's that powder stuff for?" you ask, your voice cracking hard as you speak.
"Oh, that's how my magic works," the nurse replied. "By rubbing it into your skin, it's permeating through you and changing your body's hormones from masculine to feminine. It'll also change your past and identity so everyone remembers you as female and you have the feelings and knowledge about your body of a girl your age."
She leaves it on you without touching you for a few minutes, and you can already notice the changes. Your body has way less hair now, your skin is smoother, and you seem to have shrunk inwards a little, especially your hands and feet. Memories about how to care for your body have also emerged, and you realize you feel attraction differently. Boys and men seem more appealing to you now.
The nurse looks at the time and says, "Okay, now it's time for the big changes! These might feel really weird, but I promise they won't hurt at all. They'll probably feel really good, in fact."
She reaches between your legs and cups your penis and testicles in one hand. She gives a firm tug, and you gasp as they are pulled from your body as neatly as a piece of clothing. Your eyes widen as she holds up the detached manhood, and as you look down between your legs and see a flat smooth mound.
"This isn't your penis anymore," the nurse smirks, setting the genitalia aside and putting it into some kind of storage. "I'll be giving it to a boy who everyone thinks is a girl." As she moves back to you, she sits down and says, "But now to do your parts!" Her finger rubs along the flatness where your cock and balls were, and you feel it ease inside you, making you pant and bite your lip.
"Your vagina is forming nicely," she says softly. As she continues to rub at you, the opening between your legs extends into a pair of lips and deepens into you, more parts forming at its top. Your hips seem to widen as it forms.
Much to your disappointment, her finger slowly emerges, but then you moan intensely loudly as her thumb carefully rubs a tiny nub at the top of your newformed folds. "And you've got a nice, sensitive clit!" she adds. "I bet you're gonna have a lot of fun playing with your body when I'm finished with it."
She moves to stand over you, and tells you teasingly, "Now to do the last part." She moves her hands down to your chest, rubbing her fingers lightly over your nipples.
You whimper with pleasure, astonished at how sensitive they feel now. "Wha-why do they feel like this?" you breathe, your voice now obviously a girl's.
"Oh, girls really like it when someone plays with our nipples, it makes us feel good," the nurse explains. We... us... it's strange to realize now you don't simply want to be a girl, you ARE a girl. As if to prove it, your nipples swell under her touch, the areolae widening and protruding, the tips expanding into teats to be suckled on.
Her hands move down to your chest and it expands too, soft breast flesh forming that's sensitive and supple to the touch.
This feels better than anything you ever felt as a boy, and you look up at her, your face a picture of pleasure, and manage to get out between moans and pants, "Please... more..."
"Do you want to get to your peak?" the nurse asks. You nod. "Good girl," she breathes. Hearing someone calls you that gives you so much euphoria beyond sexual pleasure. "You play with your pussy, I'll play with your chest."
You do as she suggests, and as your fingers insert inside you slowly your arousal surges still more. You shut your eyes and imagine handsome boys kissing you, kissing your neck, playing with your chest, sucking your boobs, making you suck their cocks, eating your pussy, filling you up with their cocks, pounding you while grabbing at your chest... it's too much! Your mind practically goes blank for a second as you hit your peak, shaking on the bed and against your hand and in the nurse's arms. All you feel like you know is that you're female now, and you love how it feels.
Slowly reality irises back in, and you see the nurse smiling at you. "Did that feel nice?"
"Y-yeah," you breathe.
"Good," she replies. "Now, get your clothes back on and go back to class. And never forget- you're a good girl!"
You giggle and dress in the clothes you see on the floor, which you faintly realize aren't the male uniform you undressed out of. You pull on a pair of panties and a bra, put on a pair of tights and a cute frilly skirt, button up a shirt and blouse, and step into some neat black shoes.
"Um... thanks," you say softly to the nurse as you leave, and she gives you a grin and waves goodbye to you. You like the idea of this new life, you think to yourself.