-- no buts about it, this is crap.
Accompanied by imaginary (and probably enthusiastic) David Attenborough, we continue our exploration of the back-door world.
The butt is actually a pretty cool place. It manages to be both the complicated end of a pretty complicated digestive system and a playground for the human impulse of 'hey, I wonder if that feels good?'
The butt is kind of like a spaceship airlock. It's watertight, it's even air tight, more or less, thus giving us our ability to fart the alphabet, with practice (I'm on 'F', how about you?). This miracle is worked by two sphincters, and they do their thing and -- once we're potty trained -- we don't do our thing unless we want to. These sphincters are not generally under complete conscious control but they can be, with practice.
Beyond that gateway to the soul, lies the rectum and this is the fun part where the magic healing cock finds it's natural home. Most of the time, this chamber of delight is empty. There may be the occasional bit of junk or cruft because the human body works very well, not perfectly. All respects to the mildly infamous anonymous on fansecrets; just because you stick your finger in your butt and wiggle it around to deal with constipation and discover poo there does not mean crap is present in the rectum all the time. It is perfectly acceptable to stick a finger, a dick, a toy or various other items in the butt and not expect to encounter significant amounts of crap. For those writers who are adventuring to deep penetration or fisting, the likelihood of encountering some stray crap increases -- thus pre-adventure enemas can be added to the erotic menu. Some folks do enemas every time before anal sex, others never do, do, do, doodoo, doo whop an either of those options are perfectly acceptable solutions to doo-doo. Some people use condoms for the neatness factor in anal sex, too.
Anyway, as we peer into the mystery that is the butt, we are unlikely to find crap, except in those occasions where the person is feeling the urge to go grab an old copy of Mad Magazine and spend some time on the porcelain throne. The urge do defecate is triggered by the pressure of crap in the rectum, therefore you can pretty easily suss out when you've got crap in there and when you don't. However, most practitioners of the anal olympics don't get too traumatized by the appearance of a bit of accidental poo -- it's sort of a risk of the butt end of the business.
Another thing you might find in the rectum is the prostate, however only fifty percent of the human population has one. Sad isn't it? So many people without prostates ... how do they manage? That's right, women don't have prostates. It's kind of a trade-off, (most)women don't have prostates or dicks and (most)men don't have vaginas or uteri. That's right, men, of the more or less human of this day and age, do not have uterus -- they especially don't have a uterus branching off from the rectum. Remember the poo? Mammals have solved the poo/baby conundrum by almost entirely separating the reproductive and waste production tracks (no the platypus does not count). If you want mpreg, take a little time to come up with a pseudo science/magical explanation for this issue. Just like characterization or spelling, having enough mcguffin explanation to allow readers to hand wave your babydaddy is part of decent writing.
The prostate (which is not prostrate) is a magical little gland embedded in the muscular wall of the rectum, just past the anus and about the size of a walnut. It is not a bundle of nerves, or a muscle or a bone/vein/hamster or spiritual center of the catching partner. It's a gland and it's actual job is to make stuff when a guy comes. Because it's part of the process of ejaculation, it's activities and sensations get tied up with the pleasure of orgasm. That's why, along with the fact there are nerves in that gland, it often feels good when it's stimulated.
Often. Not always. Just like some women love having their nipples played with, some hate it and some don't care -- men have a variety of reactions to people messing with their prostate (they also have a variety of reactions to having their nipples played with but that's a rant for a different day). It is not automatic that someone will find anal sex pleasurable due to the presence of the prostate and the prostate is not the only way to get pleasure when getting fucked in the ass. Which is good, because a lot of women like anal sex too and they are denied the prostate experience.
Remember the rectum and its ability to tell when there's crap in there? There are nerves in the rectum and they respond to pressure and other sensations. The anal sphincter is the same way. Because of this, it is quite possible to really, really enjoy anal sex without getting your prostate stimulated. Just the pressure of dick/toy/fingers/etc can feel pretty nice pushing and moving against the rectum and the butthole. As a special bonus for women, the closeness of the rectum to the vagina means they get a certain amount of reflected sensation in the vagina via butt fucking -- or so I'm told. That's supposed to feel pretty good too.
The rectum is semi-permeable mucus tissue, it secretes a tiny amount of mucus to keep from irritating itself when it's empty and thus collapsed. This does not mean the bad manga self lubricating anus -- I've never even noticed the presence of slippery mucus up there, just the awareness that it's moist in there. It does not (or should not, pre fucking) squirt, ooze, spill, dribble, or otherwise seep. Seep and ooze are words, by the way, that should never appear in your sex story. I don't care what the thesaurus says. Being a semi-permeable membrane is a very special thing; things that go in the rectum can be absorbed by the rectal walls. This is why it's possible to get drunk or caffeinated on an alcohol/coffee enema. It's also why you want to think a bit about what kind of lube you are using -- soaps sting, so does menthol rub/tiger balm/spicy soup and salty broth. Basically, if it stings to put something up your nose, it will sting to put it up your butt. Still have questions? Your butt is right there, and fundamentally identical to a man's butt (or maybe even a man's butt). Sorry if you put capsicum cream up your ass ... I'm not responsible for your malfunctioning common sense gland.
So, to recap, there are a few things you might find in a healthy butt. A prostate, a sphincter (known in purple prose as the muscular ring or the love bud), and possibly, rarely, a small amount of crap.
Things that, dear god, one hopes you won't find in the butt.
*cups of creamy fluid
*peanut butter
*quantities of unexpected poo (scat stories with planned poo are perfectly understandable)
*your soulmate
*'essence'
*blood
*a hymen
*the chamber of secrets
*roses
*sea life (please god, no) I have to take this back. Look here, if you dare:
http://mcparrot.livejournal.com/15356.html*weapons of mass destruction, no they weren't in Iraq and they're not here either
* a direct connection to a man womb
*Waldo
Next time on Butt Confidential ... where's the butt, bub?