You put the final piece onto the machine and step back, marveling at your creation. You had finally done it. A year and a half of work finally culminated into this: a machine that could transport you into any media that had skunks in it. It is a very specific feat, but you had your reasons to build it. Perhaps too particular, but you had. A long-time dream is now ready to become reality. You were a scientist that specialized in skunks, a science not too many people thought was interesting but you liked it. Loved it even. Skunks are your favorite animal, ever! You had studied everything about skunks and now you were moving on to other types of skunks: the ones you grew up reading and watching since you were 3. You were only 20-something, pretty young for such an engineering feat, now but adding all the different skunks' dimensions to the machine brought back all the fun memories I had.
You fire up the machine and try to decide where you wanted to go first. On a whim, you decide to let the computer randomly choose the location. You grab your bag of equipment and step into the pod. You suddenly feel a little strange as your molecular structure started to shift to the new plain of existence, one atom at once. You close your eyes as the machine does its job. The dimension was also being generated in the meantime...
You open your eyes and see you are in front of the elite four building in Shinnoh. You remembered you had used your old Diamond game file for data into the machine. You look at the pokemon in your party and sure enough, it was the same team from back then. You were glad that one of the pokemon was a max friendship skuntank. Your "little friend", your favorite. "Perfect", you say, sitting your backpack down and looking for the ingredients to make a poffin and pull them out one at a time. You measure out just enough laxative to make the skuntank poop a lot but not too much. It's part of the experiment about skunks. You might be a mad scientist to some, but you still had some compassion toward your test subjects. You hoped that the skuntank would hold it for you and not just let it out like most your subjects did. Reason why the friendship stat was important. You make the spiked poffin and throw out the Skuntank. He was glad to see you so you did look like a trainer. "Hey, Skuntank. We are going on a little trip together and I want you to do something for me." The Skuntank cocks his head. "I want you to not poop nor pee throughout the entire trip and I'll give you a gift." His ears perk up at the sound of a gift, not realizing how difficult that could be. "Good boy." You give him a little rub on the head and give him the poffin. Skuntank eats it happily. 
You start on a journey back to Twinleaf town with Skuntank in tow. You didn't want to force the Skuntank to poop. You wanted to watch it hold till he couldn't anymore. That would be pretty evil for some... but, coming to think about it, you treated skuntank so well up to that point, that you kind of had the "right" to do it.
After a few minutes, You notice the Skuntank's belly was slowly inflating. That was a good sign. You continue to walk as if you didn't notice. Meanwhile, the Skuntank was already feeling a bit of discomfort in his bladder and intestines. The laxative was brewing trouble inside of him and he already had to pee before being freed. He knew he had to hold it but he didn't know for how long. He had been in the ball for a while now so he hadn't had a chance to go in a while and adding the laxative worsened it 10 fold. You didn't consider that he probably already had to go. The belly kept growing somewhat and the poop was pressing against the anus, gently at first, but later, it's going to be stronger... The urine was being saved up and the bladder and bowels would soon fight for space in that round tummy.
An hour later and you could really tell he was holding. The Skuntank was more gassy then usual and he stopped multiple times to prevent a mess. His hole was a bit open and one could see a brown matter while looking through it. Meanwhile, the penis was not dripping, but looked shaky. His stomach  was huge and taut now and you could hear his bladder was full, due to the ominous sloshing. You thought about just stopping now and just letting him go but this was too fun to pass up. This makes you feel a little guilty... This was one of the reasons you decided to do this. You walk over to Skuntank and noticed he was already leaking pee, now dripping on occasion. "Wanna stop for a bit?" He nods. You could smell his Stench getting worse so you took this time to pull out a vial and take a small piece of his fur. "Skuntank, use your spray." He was rather confused by this but he opened his tail and let out a small stream of spray. You scooped it up in the vial. You were glad that your research had got you used to bad odors. Being skunked did not feel so bad anymore. Skunk spray was now your second nature.
You labeled them and sat them in your bag. Now you just had to wait for the inevitable. You thought for a bit and had a fun idea. You slowly push on the Skuntank's bladder, causing him to wince and spurt a little pee out. He was giving the best. You grab a 3rd vial and catch the pee in it. You might have gotten all the pee you needed but it didn't stop you from trying to make him pee the rest. You push on his bladder more as the Skuntank whimpers. He didn't understand what you were doing but for some reason he liked it. He was enjoying the struggle in the end. Perhaps he heard what you were saying to yourself in your room, back when you were 8. He finally gives up and lets out a jet of pee onto the grass. You watch as the Skuntank slowly relax and almost start pooping. Before he could stop himself, a turd start to push out his ass onto the grass followed by 3 more. He sighs with relief as he bares down and starts pooping more. You take this chance to collect a little of it while he wasn't looking. "Good skunk." You give him a treat and a petting on is head.. He is a little confused but takes it anyway. "Holding means treats? I should do this more often." The skuntank thought. And that's how you trained your pokémon into holding it.
After he finishes, you return the skuntank to his ball. Maybe after all this, you could come back and do this again but for now, you take the return remote out of your pack and push the button, sending you back to the pod. You immediately sit your specimens in a special area. You couldn't wait for the next trip to make a skunk mess themselves.