Firstly, gender

  Male
  Female
  Not tellin'

How often do your mess yourself?

  Never/ only due to sickness/ injury
  Once or twice
  A few times
  More than just a few times...
  I've lost count, I use my pants more than the toilet...

If you have, how bad is it on average?

  Never done it/sickness and injury (good on ya!)
  Just skid marks
  A small unnoticeable lump.
  A noticeable load in the back of your pants
  A large mess in the sagging your pants
  Totally full or overflowing. (Complete potty failure)

On to the scenarios:
Say you're in school (or are back in school), and it the last class of the day. You sit in the back of class next to the door. You've been holding it all day, and when you ask to be excused, you're told to hold it due to there only being 20 minutes left. But you might not have that long. So you

  Sneak out anyways, no way you'll risk that.
  Try to hold it. Still unsure you can wait that long.
  Try and hold a bit longer and mess yourself discretely. Sure its embarrassing but if no one notices you can clean up in the restrooms.
  Give in and mess yourself in defiance. That'll teach them to not make you hold it!
  With a grunt, you make it obvious what your doing in your pants. As you fill them up, you're told to report to the nurses office and promptly changed

Say you are on vacation with two or three friends. You share a hotel room on the top floor of a beach side hotel. The doors use those plastic slide-in keys that seem to never work when you really need them. As you all hang out on the beach, you decide you've held it long enough and head back inside with one of the keys to use the toilet in your room. But the key doesn't seem to want to work. You're close to giving up, but you decide to...

  Pull down your pants and poop on floor in the corner of the hallway. You'll most likely end up on the surveillance cameras... you're clean though!
  Forget the door, rush to the lobby and ask to use the employee restroom. But there's a good chance that you'll poop your pants in/ on the way to the lobby...
  Persevere and keep trying till the bitter end. Maybe it'll work. However, due to how shaky your hands are, it's mostly luck if the key will work or not. Your will starts to crumble...
  Bend slightly and let it happen. You feel incredible relief, and return to a wobbly footing. With the relief achieved, you calmly get the key to work after a few more tries. Time to clean up?

You have the whole weekend off. Alone in the backyard, you're reclined in an outdoor chair with music and a drink. Your desired pet is sleeping peacefully on your belly. But the moment is somewhat ruined by your urge to poo striking suddenly. So you

  Sigh and take your pet off of you. Waking them up, you head to the toilet.
  Hold it till you're turtle-heading. Let them get a little more sleep but risk messing your pants.
  Hold it and wait for them to wake up. But you have no idea when that'll be. There's a good chance of an accident
  You carefully, adjust yourself to make room as you willingly fill your pants up. Not like your pet will care right? You're face flushes red as you settle back into place...

Your S/O (or desired s/o) is spending the night at your place. You only have one bathroom, and pause what you're doing for a bathroom break. You both stop in the doorway, and briefly insist you both need it more than the other.

  Walk past them and shut the door without further arguing. As you're letting loose, you here some panicked knocking on the door that gradually gets quieter before stopping. As you finish up, you open the door to find your s/o in tears on the floor. An incredibly obvious bulge in there pants marking their accident
  You continue to argue and block the way until they freeze and instinctively double over. A quiet crackle is heard as they grunt and push. Since they obviously don't need it anymore, you turn to go... but all the extra time arguing pushed you to the limit.
  Offer them the toilet and try to hold it. But you feel you just sealed your fate
  Give in and mess yourself. An obvious load bulging from your backside. They stare with a sympathetic look on their face and apologize. Offering to help you clean up after they are done.

While on a hike, you and your friend get halfway down the trail when you realize how much you should have gone before starting the hike. You

  Step off the trail and try to find a secluded spot to do your business. You don't really have anything practical to wipe with
  Try and hold it. But this is gonna be another two hours sooo...
  Tell your friend you have to go, and ask for some kind of bag or container to go in. Not saying they'll actually offer you anything, but it's better than going in the woods
  Hold it as long as you can. Poop your pants discretely when your friend isn't looking and try to hide it from them
  Apologize to your friend and give in. They awkwardly stand back as you crouch and fill your pants, before stumbling to your feet

(Back to school) It's the middle of the gym period. Obviously you have to go pretty darn bad, and you're in the middle of a Football/soccer game. Playing as goalie, the teams are spread thin, and the game is close. You ask if you can go to the restroom, but are denied. You'd also be letting down your friends if you left the goal wide open. You decide

  You can't hold it much longer and run back to the school building to use the restroom. This ticks off your friends and gets you in trouble. But when you gotta go you gotta go
  You try to hold out, but every ball sent your way makes you slip closer and closer to a change of pants. You kinda suck when doing the potty dance half the time, But if you're lucky you'll make it just in time.
  While the game is on the other end of the field, you slowly begin to mess your pants. relived, you can play better, and just hope nobody notices
  With a determined grunt, you ball your fists and push with all your might. With that immense weight relieved, you try to get into a good position with the mess in your pants keeping your legs apart. But hey, game on

You're alone at home. Spending a day off in comfy pjs. You've been holding it for hours, entertained by the screen of a game. it's online, and you're doing incredibly well. But it can't be paused, and you could get booted from the game due to inactivity if you just left. So you

  figure the game is great, but not so great you should soil your pjs. You give up and go to the restroom just in time
  Hold it in and hope to win. The need may throw your skill off a bit, but victory is so close. Maybe you'll make it
  Focus on the game. You didn't come this far to lose. While totally engrosed in the game, your need builds and you steadily fill your pants. You realize halfway through the accident what you did, and sigh. You absolutely crushed the game though.
  Lift yourself from the seat a bit, allowing your pjs to balloon outward with the mess filling them. Relived, victory is assured.
  find a brief moment to pull your pjs aside and poop on the seat.

Speaking of pjs, you've just woken up on a calming day off. You sleep in for a while but still feel you could use some more zs. But your need for a toilet is prevalent. So you

  Grumble a bit, but get up to use the toilet. Brr its cold :(
  Snuggle under the covers and hold it. Enjoying the warms of your bed. Try to make it at the very last second... you CAN hold it right?
  Fall back asleep. Waking up later to find a strange warmth. then the need strikes you again. You've wet the bed, and are seconds away from doing much worse. As you get out of bed, you lose it in the doorway, and strain as your wet pjs are filled with a mushy accident... whoops
  Roll over and push. You feel relived and warmer than ever, falling back asleep with your mess. Are you wearing a diaper by chance?

Lastly, you're offered 100 dollars by your friend. They dare you to take the money and poop in your pants.

  Of course not, you shake your head at them for their immaturity
  You nervously accept the cash, and try to get into a good position, before letting it all out. Once you start, you can't stop, and your friend snickers and tries not to laugh for the whole process. You feel weird... and embarrassed. But a little richer
  Nothing new to you, you confidently take the money and squat down. Comfortably messing your pants, despite the laughter.
  You take the money, and chuckle a bit. You're wearing a diaper, and mess to simply uphold the bet. Your friend is a bit confused, and salty about their wasted cash.

That was a long test. What's your current condition btw?

  Um good? Clean and all that.
  I kinda have to go, so let's hurry this up
  I wet myself during this sooo
  Messed during this test...
  Going...right...now...