This sounds pretty outlandish to you, all told. So you figure it'll be fun to try the one that sounds most dramatic to you: changing gender. Sure, you can lose or gain lots of weight or muscle, but turning from one sex to the other would be a much more striking change. You lock your door, pull off your pajamas and stand naked in front of your mirror, and then say "Gender".
Instantly, your heart races as you feel yourself start to remold in response to the spell, and your doubts are washed away as before your eyes you transform. Your figure starts to turn smaller and more petite, and your muscles follow suit as they become more lithe and your hands and feet shrink. Not only are you now shorter, thinner and less muscular than before, your figure seems curvier and your shoulders have shifted inwards while your hips have expanded outwards. Even your skin seems smoother and your body hair has almost vanished.
The changes shift to your head and face and seem just as dramatic if not moreso. Your neck narrows and the bulge of your larynx vanishes, and you hear your your voice increase in pitch significantly. Your features shift around, your cheeks and jawline become softer, your lips are puffier, your hair lengthens down past your shoulders towards the small of your back.
An indescribable warmth surges through your chest and crotch as the last two parts of you to still be unchanged start to give way. Your nipples turn erect and swell up, and to your surprise you love how it feels to have something expand outward after so much of you has contracted inward. You breathe heavily as your breasts develop, and ache to have the swelling mounds cupped and massaged, or their aching tips rubbed and pinched and licked and sucked.
The contracting sensation returns, and this time it's at its most intense as it weans its way into your penis and testicles. Your shaft rapidly recedes into you, your balls pull up inside you, and as this happens a sort of clarity comes into your head. You aren't male anymore, now you are female. You accept this as you see your cock recede into a tiny sensitive nub, and your scrotum tucks inwards and splits open along its epicentre to form the lips of your new pussy.
It takes a moment for the shock of the change to subside, but once it does you look at yourself in amazement. Your reflection shows a girl who looks very like you, just the opposite sex. There isn't any indication you were a boy a few minutes ago, it's like your body was born as its opposite. "The book really works..." you say to yourself, astonished by your girl's voice as you speak. You wonder what to do next...