You start by popping the pills, never particularly good at following instructions you don't take one, or two, but three...just because that happens to be the number that falls into your hand when you shake them out onto your palm.
Stripping your clothes, even as a strange sensation slowly spreads across your skin, goosebumps rising everywhere, you laugh as you smear with your hands the toner around your eyes, nose, lips, and finally your penis, where you let your hand linger, giving it a good firm tug and stroke, "This is going to be so cool. My bros were laughing earlier, but at the party they're going be so jealous when I show up the stud."
Even as you grab the anthro donkeyboy kit's muzzle and ears, applying the glue and sliding each into its respective place, you fail to notice that coarse hair has already rapidly begun to sprout from your body, your skin thickening and darkening into a donkey's rough hide. You slip on the contacts, and with a slight wince, shove the tail onto a slightly bloody spot you've cut with the scissors right above your firm butt. "Should be good." you say to yourself, looking around to see if you forgot anything and spotting the enormous donkey-penis with a wry smirk.
"Woah!" you exclaim, abruptly catching first sight of youself in the mirror, your former smooth, muscular body noctieably furrier, your swollen lips moving with the muzzle attached, as if it were somehow part of you. Even the long ears you've attached, rising past your head, seem sensitive and alive, like...you could move them. Oh, shit, wait, you can!
Your balls have swollen too, and your cock stands fully erect, comically small for a donkeyboy and disproportionate to the swollen, almost black, sack beneath it filled with two orange sized spheres. Smearing glue onto the donkeyboy penis, you ram yours into it, and snatching the hooves, the final touch, you apply the glue and step into them.
In the mirror, you see your coarse fur and pelt has nearly fully developed. And, the need for sexual release is almost unbearable. You begin to jack your enormous donkeyhood, unaware of the slippage your fast stroking is causing as the penis begins to meld with your own...oblivious of the kit's firm warning as you begin to feel sensation throughout the donkeycock's entire, huge, fat length, a length considerably longer than it otherwise should have been as the swollen glans stretch towards your muzzle.
Just as you think sweet release is imminent there comes a brisk knock on the door, and it swings open. As it does, you hear your the pledge master's voice, asking "Heh, bro, I found this silver halter-thing downstairs, I think it fell out of your donk..."