You picked out what looked like a large costume which looked like a huge human cock. It was enormous, the shaft alone was almost 5 feet long and it had the diameter about as wide as a doorframe, excluding the massive testicles which looked like yoga balls. Nonetheless you pick up the costume and notice an opening underneath to slide it onto your body. The whole thing looked like it was one of those inflatable costumes but it had no pump, but nonetheless you just figured it would be fun to try on still unsure if what Uncle Jack said about fetching a costume and trying it out for yourself was serious or not.
Either way you take off your shirt and pull the whole costume over your head, and the insides are dark, no armholes, and the whole thing came down to your waist. It all felt surprisingly light thankfully, but then you suddenly felt something was off with your waist when you suddenly felt a the opening suddenly clench tightly around your hips waist and stomach, and the walls around there suddenly felt hot and sticky.
"Gaaah!!!" You cried out and fell over, trying to push the ginormous costume off of your body, but the damn thing wouldn't budge. Your heart started racing faster and faster and for whatever reason your stomach starts throbbing to the beat of this. You soon start to sweat as you reached down to try and pry your body away from whatever sticky substance was sealing you inside the suit, but when you reached down with both hands you couldn't pull them back up.
"W-What?! N-No! L-Let me go!! Help!!" You cried out but to no avail as you started to feel strangely aroused. As this happened the inside of the costume got warmer and as you began sweating the stench of sweat and sex filled the insides of the costume making you wince and want to throw up. What's worse was that the sticky liquid sealing you inside was traveling upwards at a rapid rate, quickly engulfing your entire torso as you struggled for dear life, you didn't want to suffocate inside of some giant cock costume!
"Nrrrgh~!! G-Get out! S-stop! W-Why do... I..." You began to say as the same arousal before engulfed your body. However, you also don't feel yourself getting an erection between your legs, in fact your legs felt hauntingly empty. You also feel your hands swelling while also throbbing, and soon all bone and muscle in them leaves and it is shifted into your spine to help support the rest of your body. Your hands felt like they were growing, throbbing, getting larger and rounder by the second, fingers growing and into large throbbing roots that connected themselves to your back and lungs which also connected to your throat.
The smell inside of the suit only grows more intense as the liquid reaches up to your neck, and you felt all the muscles in your back stiffen and tense up making you stand up straight uncontrollably. You began crying now really thinking you were going to die and suffocate in this constricting hellhole of a costume. But then you look up and see a tube extend down from the top of the costume, not big enough for your head but big enough to let in plenty of air, and the your back's stiffening and swelling was pushing you towards this tube. You felt something weird now bubbling up at the back of your throat, and instinctively you needed air so the first thing that you did when this tube was close enough was wrap your mouth around it.
However when you do this the sticky liquid substance suddenly surrounds the tube and locks your mouth in place, leaving you completely stuck and unable to pull away. You cried out and screamed as much as you could but soon felt a churning feeling in your hands travel into your lungs and quickly made its way up your throat. The sticky liquid substance was now engulfing your face, eyes, nose and mouth, and you felt like you were going to vomit. With all hope lost you just closed your eyes and held nothing back, but the fluids that traveled up your throat wasn't whatever your last meal was, it carried a heavy salty taste to it that spewed out of your throat like a projectile and you felt gallons of it gushing up and out of your throat, your whole body throbbing violently as this liquid was expelled from your body and it didn't stop for a good 5 minutes. After this happened you felt your body relax, and feeling exhausted you just flopped forwards and splashed into the puddle of whatever you just threw up.
A few minutes pass and you slowly feel like you can open your eyes, still smelling that strong musky stench all around you, but the air smelled fresher than the air inside of the costume. However, when you opened your eyes you were staring at the wall of the room you were in before, but painted white in a slick and gooey substance. You felt and heard your whole body throbbing, but didn't feel your lungs taking in air, but you weren't suffocating at all... and felt like you didn't need air anymore.
You then made an attempt to stand up but when you tried to stand you slipped on the slippery substance that coated the floor below your feet which made your lower half rise up and then slam to the ground. This sensation alone made your whole body tense up and you groaned from the pain but as you did this you felt liquid travel up again and you started to drool a clear salty liquid down your chin, and this sensation also made your lower back stiffen up slightly.
You let out a sigh and a huff which was translated to a few larger throbs which was when you decided to try a different approach and roll over so you could sit up. You made the attempt, and when you did this it felt like you were hefting an incredible amount of weight, but your legs felt stronger and easily managed to roll you over onto your back which was when you say up, and saw a mirror facing you on the opposite wall.
It was at this point your heart sank as you saw what was staring back at you, it was nothing but an enormous throbbing, veiny penis with its mushroom tipped head pointed at the mirror, with thick layers of precum drooling and bubbling out of the slit at the very end, and completely covered in thick layers of cum. It even had large bushy hairy pubes that was the same color as your hair covering it. The moment you saw all of this you screamed out, but when you did this a liquid from your stomach shot up your body and you feel and see the tip of your penis head shoot out a violent stream of piss which you tasted every bit of as it coated the other side of the room in urine and flooded the room in about a couple inches of piss before you stopped. Your horrors were confirmed almost immediately as they were realized at this point, you were nothing more but a giant walking hairy cock. The only parts of the old you that were left were your legs and feet, which were much beefier and larger to support your huge phallic body. Your arms now had shifted into being your two enormous testicles, each one rivaling a yoga ball in size. Your lungs were now connected to your former hands, as most of your internal organs had rearranged yo form one giant scrotum, with the only exception being your stomach which seemed to have become your new bladder. Your ass and anus were no more, unneeded, and now replaced by your hairy testicles.
The worst part about this wasn't the looks, the loss of dexterity or mobility impairment, but the feeling of your testicles and bladder slowly filling up again automatically, like a timer counting down to whenever you had to spew one or the other foul smelling and tasting liquid. You tried moving your hands, but this only caused your balls to churn, causing your spine to stiffen more every time. Putting two and two together you figured this was only accelerating the production within them, and moving your mouth and trying to speak did the same with your bladder. The strangest part you felt, was that when you spewed out your seed it felt incredible... like the biggest rush of your life! Then when you took that piss it felt like your entire body was relaxing itself, and despite each taste your whole body was filled with an incredibly pleasant feeling that outweighed the consequence of the foul stench, and strong taste.
You slowly make an attempt to stand up again, and succeed! You then slowly hobble your way over to the door, trying to think of a way to open it without hand when suddenly it opens for you. Then your heart drops even further making you go flaccid as you see Uncle Jack standing there, and the mess pouring out into the room he was in before. You were so fucked...!! Maybe literally considering what you were, and what's worse your fear accelerated your bladder's filling and made you feel like taking another large piss.