(note: I've copy-pasted a large part of the Shaggy Dog Story in here. Hope the author don't mind)
As you run down the stairs, you hear Uncle Jack on the phone talking to your mother, "Don't worry, sis, I'll keep him on a short leash! He's down in the basement trying on costumes right now..."
You screw up your face, and mutter, "A short leash, huh?"
You look at the loincloth and fake green vine on the rack in the basement. You pick it up and look at the flimsy bit of suede cloth. You sniff it, and crinkle your nose. Doesn't your uncle ever clean these outfits?
The next one is a ballerina outfit. Yeah right? You as a sugar plum fairy? You shake your head.
There's a football uniform complete with pads and helmet, but it smells like a locker room.
Perhaps the first rack is for returned costumes that need to be cleaned. You don't bother with the gorilla suit or other articles but go deep into the back of the basement store room to see what you can find that seems clean.
You notice a curtain, and lift it back there are plastic suit bags loaded with costumes. You grin, "Ah, the good stuff!"
You find a really cool pirate costume, but you want to put in a dig at Unc for saying he'd keep you on a leash. Ah, a bear costume, maybe? A stag? Haha, oh, it was deer hunting season, so you decided against that. A cow? Ah, a dog costume! That was perfect. It even came with a red dog collar, leash, and a plastic red fire hydrant!
You grin as you take the costume out of the plastic bag, and frown at the pink instruction sheet that is in the bag. It's marked "Warning: ADULT COSTUME--PLEASE FOLLOW WEARING INSTRUCTIONS EXACTLY".
You laugh, as you pull it out, wondering what's so adult about a dog costume. Though the head looks a lot more realistic than most dog suits you've seen. Not at all cartoony. However, you can't seem to find any instructions. Oh well, it was probably just there to save the ass of whoever made it if something went wrong.
You quickly strip totally naked, feeling particularly naughty. You pause before stepping into the suit and sniff it. It smells new. You grin, and shove your foot into the stretchy fur fabric leg. Your toenails snag in the fabric and your big seems to twist under your foot, but it doesn't hurt, it just feels funny. Besides your big toe couldn't really slip under up and behind your other toes!
As you come up to the crotch area, you start thinking. The costume is pretty tight, and you don't want your mother and uncle to see your privates. With this in mind, you decide to tuck it in between your legs. Then you pull it up and put your arms into the front legs.
With your hands inside the costume, you find that it's difficult to zip up the zipper. Luckily, there's a cardboard tag on it, and you manage to catch it with your teeth, a bit surprised at your own flexibility. As you pull it up, you notice something. The dog costume has teats. Oh well, it's almost on you now, and you might as well put it all on and see how it looks.
You put the collar and the head on. The first thing you note is that the colors of the world are different, tinted rose. There must be some sort of polarizing filter in the dog eyes.
As you try to walk over to the mirror, you find that you can't stand upright. You didn't notice that the costume had any kind of restraints. You drop to all four, feeling much more comfortable. It takes you just a second to realize that all four of your "paws" are on the ground, and your butt and back is parallel to it. It feels weird, but somehow quite right.
Looking into the mirror, you're amazed at how real the costume looks. If you hadn't known that it was you, you could have easily thought it a real dog. The barrel chest, the legs and paws, the snout and even the tongue seem so lifelike, and you can control it all. How does the costume manage to do that? You almost freak a bit out, but calm down when you hear your uncle call for you.