Being a witch’s boyfriend has its perks, you think to yourself as she pulls a pair of lacy pink panties up your legs. For one, you think, it makes this kind of stuff much more… exciting. She tucks your penis down, albeit with some difficulty, as it stiffens from the slightest touch from her soft hands, and makes sure it fits snugly into your underwear. It doesn’t help that she’s already naked (you asked her once if witches do all of their witching in the nude, and she told you with a wry smile, “Only in the bedroom”). She moves on to affix the matching bra to your chest. “Ready?”

You nod, but she already has the wand out. “Okay, what do you—oh!” Her eyes light up. “How would you like to try something a little different tonight?”

"Different," you ask, "how?"

She pulls a box out from under the bed and takes out an elegant violet corset. You shrug. “Sure.” She wraps it around your abdomen and laces up the back, pulling it tight around your stomach. You wheeze. “Too tight,” you say through gritted teeth. She loosens it for you. You catch your breath, make sure that none of your ribs are being crushed, and give her the OK sign.

She twirls the wand in between her fingers like a baton before tapping you on the nose. She always starts with the nose, you think as your face starts to prickle.

She traces the wand down your chin and neck, passing your collarbone, and landing on your chest. You feel your chest expand, a pair of breasts filling up the lacy bra. Your nipples, stiff and tender, brush up against the fabric and send shivers down your spine. You look down, your lengthening furry snout, black with a single white stripe running up it, gets in the way. You reach up to feel your new breasts, but your girlfriend is already doing that for you; she’s slunk behind you and wrapped her thighs around your waist, groping your breasts with both hands from behind. You moan as you raise your muzzle skyward, and the change starts spreading further down your body. Your arms and torso grow soft, thick fur like the kind covering your face. Your girlfriend slides her hands down the sides of your corset and you can feel your body conforming to the curves of your undergarments, numbing like soft dull heat. Two white stripes arc down your neck and back as your hair curls itself into long white ringlets cascading down like a waterfall.
She’s drawing herself closer, slowly undulating against you, massaging your new pelt. Her magic fingers reach your hips, and you can feel your hips widen, pulling against your panties. Your girlfriend’s arm curls around your waist and reaches down into your panties, and the best part of the transformation begins.

She guides your penis into your body; you feel it and both your testicles retract, leaving behind a warm slit she eagerly plunges her fingers into. You reach down too, but your hands have turned into stubby black paws. All you can do is pant and paw at your panties while she drives her fingers deeper inside. You can feel yourself getting wet; you moan again, the pitch of your voice rising at the end. As your breathing grows shallower and faster, your moans become progressively higher-pitched until your voice is several octaves higher than normal. With her free hand, she massages your thigh as your beautiful black fur marches down it and your feet turn into stubby pink-padded paws.

You topple over on your front, landing on your paws and knees with your girlfriend still clinging to your back and fingering your new clit. At last, you come, and as the fluids leak down your thighs a huge fluffy white-striped tail bursts from your backside, shredding your panties. You collapse as your girlfriend unlaces the corset and unclasps the bra. She picks herself up and carries you up, cupping your breasts in her slender, soft hands and squeezing your nipples between her thumbs and forefingers. You gasp and almost collapse again, but she steadies you.

You think back to all your prior experience being transformed and try to remember how to balance with such a big tail trailing behind you. “Don’t worry,” she assures you, as if she knows what you’re thinking, “you won’t be doing much standing up tonight.” She carries you to the bed and lays you down, and then, climbing on top of you and pressing her nude breasts against your own furry breasts as she straddles your thigh. She reaches over and picks up her wand. “Now I’ll show you how to really use this…”