Know your arse
In this section you will find information about the arse and how it works. We believe that knowledge can help us have a better sex life. Knowing how our bodies work – what can happen when we have sex, how to look after our bodies and how to keep them working – can help us enjoy anal sex more.
External sphincter
The external
sphincter is a muscle that holds the anal canal in shape. It
stops you from shitting when you don't want to and can stop things from getting
up your arse too. There are lots of nerves within your external sphincter so it
can feel sensations of hot and cold, expansion and touch. This muscle is
controlled by the central nervous system, the same system that controls the
voluntary movement of our fingers and toes etc. This means that we are able to
learn to tense and relax this muscle at will (most people can clench).
Internal sphincter
The internal sphincter shares the same functions as the external sphincter, to prevent any unwanted entry or exit and to hold the anal canal in shape. This muscle is controlled by the autonomic nervous system, the system responsible for controlling blood pressure, respiration rate and other ‘bodily functions’. This makes it harder, although not impossible, to learn how to control this muscle.
Anal canal
This short tube like canal is the final passageway in the passing of shit. The
area provides some lubricant to ease the passage of the shit. The outer two thirds
of the anal canal, the part you can see when you spread a guys arse open, is
sensitive to touch, temperature and pressure. The inner third, that's the part
that changes from flesh colour to bright reddish pink colour as you spread the
arse hole open, is less sensitive to touch, but very sensitive to pressure. The
whole of the anal canal is made up of folds of soft smooth tissue that give it a
great capacity for expansion. The outer two thirds are made up of the same soft
sensitive tissue visible at the opening. The inner third, the reddish pink bit, is
a mucous membrane. This absorbs fluids into your blood stream, which is why the
arse is so vulnerable to HIV. If the outer layer of the mucus membrane is disturbed
(by douching, dildos, or even just from fucking) it makes the arse more vulnerable to
infections like HIV. At the top of the canal are the 'anal sinuses' that are responsible
for producing the snot like lubricant or anal mucus that occurs naturally in your arse.
Research indicates that anal mucus is the body fluid that can have the highest
concentrations of HIV.
Anal pillows
There are three anal pillows attached to the internal sphincter muscle which
run the short length of the anal canal. The anal pillows inflate with blood to
prevent shit from coming out of your arse, when you don't want it to, and to
prevent things going up your arse too. They need to partially drain to allow
you to shit (or allow anything in). They do this by responding to signals
transmitted from the brain. You can feel sharp stabbing pains when the pillows
aren't drained and you are trying to shit (especially if you strain too
hard) or get fucked (or stick something up your arse). The veins that
supply the blood to the pillows are the ones that can become piles,
which are also known as haemorrhoids. It's these pillows that place large
quantities of blood in your arse and accounts for the blood found during or
following anal sex. It's this blood you can see on toilet tissue after you
have been fucked or passed a particularly large or hard stool.
Rectum
This is the last section of the intestines which, along with the colon above it,
absorbs excess water from your shit. The further away from your stomach the waste
matter in your intestines is, the drier it gets. When you have diarrhoea and you
pass watery shit, this is because your body shuts down the absorbing function in
response to the infection it thinks is in the contents of your bowels or the water.
The rectum only contains shit when your bowel is full. So a good dump before you
get fucked should be all you need to do to be clean up there and significantly
reduce the chances of some unpleasant mess. This part of your arse is like a
sponge as it is so absorbent. When a man ejaculates (comes) inside the rectum,
the semen is absorbed directly through the wall of the rectum so that any virus
in his cum, such as HIV, has an easy route into the blood stream. Research
suggests that there are some differences in the cells that make up the lining
of the rectum compared to those that line the anal canal. These differences make
it easier for the lining of the rectum to be disturbed or damaged and so it may
be more susceptible to infections.
The rectum contains relatively few nerve endings and is therefore less sensitive. In general it transmits mostly sensations of pressure. As this is the continuation of the anal canal, this is another tube like structure of between five and nine inches long, made of loose folds of soft smooth tissue. It's worth remembering – the average length of a British cock when erect is between five and six inches, so most cocks only get as far as your rectum. Normally the rectum is more open and spacious than the anal canal, but also shares its capacity for expansion.
While the rectum is tube like it's not a straight tube. Instead it has two curves along its length. The lower rectum tilts forwards towards the navel (caused by the pubo-rectal sling – more of that later), and after a few inches, curves in the opposite direction towards the backbone. The second curve is usually more ‘adaptable’ than the first and rarely a source of discomfort. The pressure sensation in here when shit is present sends the message to your brain to go empty your bowels, which is why having a cock up there can make you feel like you need a shit. When you have a cock or a toy in your rectum and you feel like you need to shit, try reminding yourself that it's because your arse is full that your brain is getting this message because your arse is full of cock.
Chemicals or spermicidal lubricant, such as Nonoxynol 9, easily irritates the lining of the rectum. This can cause chafing where the lining of the rectum dries up and starts to peel, similar to the way your skin peels after sunburn, causing it to become itchy and very unpleasant. This can remove layers of cells from the lining of your arse making it more vulnerable to infection.
Rectal muscle coat
These are the muscles that support the entire length of the rectum. These
tighten in stages along the length to move shit through the rectum and out into
the world – this process of muscle contractions used to propel the shit down is
called peristalsis. That's the same process that snakes use to propel their food
through their bodies – muscles constrict and expand to push food down through
the intestines.
The only sensations that the rectal muscle coat responds to are pressure and bulk. Some men say they can feel it when a man comes inside their arses but physiologically that's not possible. It's probably the cock spasms as the man ejaculates that they can feel against the sphincter, or the cum as it dribbles out of the arse across the sphincters, which are responsive to temperature, touch and movement.
The tension level of these muscles varies from person to person. Rectal muscles are not as powerful as the anal sphincters, however if they are tense the insertion of anything can be painful. It can expand to roughly eight times its size in volume, though not in length.
Pubo-rectal sling
This is a strong supportive muscle that creates the first curve in the rectum.
It's one of the most powerful muscles in the body after the tongue. The muscle
responds to pressure or poking by clamping down to close the rectum and this can
prove painful when getting fucked, fingered or toyed with. It's when a cock stabs
this that you get that ‘whoa get the fuck out of me’ sensation. Straightening out
the rectum a bit by adopting a position where the knees are drawn up will help avoid
this. Try squatting down over the cock, lying on your back or your side with your
knees drawn up to your chest, or on your knees bringing your chest as close to the
bed/floor as you can.
Prostate gland
The Prostate Gland produces
fluids that are added to cum and, because it surrounds the urethra, it also helps
control the flow of piss. A lot of the pleasure we can feel when getting fucked comes
from the cock rubbing against the prostate, and for this reason it is often referred
to as the male g-spot. Here's how to find your partner's prostate:
Get your man to lie on his back with his legs drawn right up, his knees held to his chest. Lubricate his arse, and then insert a well-lubricated middle finger into the arse hole. As the finger goes in curl it up so that the tip of the finger is hooking up and pointing behind the pelvis towards the cock. The prostate is there about an inch and a half in. It feels warm, rubbery and smooth. Flick or run the tip of your finger crossways against the prostate. This usually gives the owner sensations of intense pleasure.
Sigmoid colon ⁄ anal fold
This is the
collection place for shit before it passes through the rectum into the anal canal
and on into the world. The nerve endings here are similar to those in the rectum,
responding only to sensations of pressure. It's also able to expand
to larger than its normal size. When a cock, or something similar, is put up your
arse, usually only the anal canal and the rectum are involved. However dicks, dildos
or anything longer than nine or ten inches may pass through the rectum into the
lower colon. This usually occurs without difficulty, as the muscles tend to relax
at the same time as the other anal and rectal muscles.
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