You put it on. (Transformation)

Before you can change your mind, you reach back letting the collar wrap around your neck. With a click the collar seals around your throat and that instant your body reaches an instantaneous orgasm. Whether it was from the excitement or an effect of the collar it self... what you know is you went from horny to climax in that moment spraying your girl cum down your inner thighs.

After cleaning up the new mess, you put your dress on and finally leave your bedroom to let you maids and ministers know you are safe. As you move away from the room you notice the haze of lust in your mind begins to clears however the sluty collar you wear is a constant reminder that on some level you have accepted Bowser as your master. Knowing you might be his sex **** any time now keeps your sexual excitement from ebbing.

As the day drags on you begin to feel unwell. You are itchy, especially near your tail bone and you seem to be developing a headache as you feel pressure at your temples.

Excusing your self early, you return to the bedroom to try and rest. To your surprise however, the lust returns unnaturally quick, only moments after you reach your bed. Is it a smell or something in the air? Hopefully it isn’t some weird association with how many times you masturbated here. Speaking of which they say an orgasm can help with headaches...

You pull out your moch-turtle-dick dildo, a poor imitation of Bowsers cocks made from your description, and use a strap-on to attach it to a thick pillow. This piece of sex gear makes you think of Daisy… she is the one who left it here after one particularly vigorous sleepover. You wonder if that slut has these sorts of problems too.

You squat down, pretending you are mounting lord bowser, your king... your master. The collar tight around your neck reminds you of your new owner. Fantasy takes over as you lift your hands behind your head in a lewd display, showing your body off as you ride Bowser. He lets you ride him, he lets you probe how much you want it. And you thank him, thank him for letting have his giant cock.

Maybe because of your acceptance or because of the stimulation… either way suddenly the pressure in your temples gives way to pleasure as something suddenly pushes out of your body in those two spots. The same happens at your tailbone and the combination sends you into a sudden climax robbing you of your balance. You collapse on the bed spasming and feel... something between your back and the sheets.

Exploration reveals the start of a tail… and judging by the wave of pleasure you feel when you touch there, it might be an erogenous zone. Suspecting the truth you go to the mirror and lift your hair revealing the start of two horns, Bastard… he’s turning me into a Koopa…

You try to remove the collar but find nothing. Your fingers grow frantic, spinning it around your neck while you try to look at it in the mirror. Examining the reflection reveals the hinge and latch are gone also... the words now say 'Koopa Slut' instead of 'Peach Slut'.

Shit…

You can’t do anything about it no except maybe masturbate again....

After another couple of orgasms you are exhausted, so you decide to sleep and come up with a plan in the morning.