Okay, a few corrections and comments:
1) urine for ALL humans is supposed to be sterile - not just women... someone kind of - perhaps unintentionally - alluded to that women's urine is sterile above which could infer that me's is not...it if for everyone...BUT:
2) urine is sterile ONLY for a little while. After it has left the body it eventually becomes almost rancid
as bacteria etc. then begins to multiply. Hence why it changes odour after it's been out of the body for a while. Anyone who has smelled old urine in an alleyway can attest that it does not smell the way it does typically as it leaves the body. That's because it is no longer sterile after a while. SO - particularly for women - it is possible to have bacteria, etc. from urine ON the human body if it's gotten trapped onto the body. If you showered in the morning, and across the day have urinated, eventually small amounts of that urine will remain on the body until you wash again (no matter how well you wipe yourself), again particularly if you are a woman - women have lots of places where small amounts that are originally undetectable can remain.
3) fecal matter is much the same way - no matter how well you wipe and how clean you appear to be, if you have had a bowel movement after you've showered, then until you shower/clean up again you'll have bacteria that remains - that is immediate as soon as it leaves the body, unlike urine, which initially leaves the body as sterile.
4) Having said both of those, it's probably best - and in a perfect world we'd all be doing this - to shower and clean up BOTH areas before engaging in intercourse, oral sex, analingis, manual stimulation, etc.
Also, it's very wise to scrub hands before ngaging in manual stimulation as well.
The sheer fact of having intercourse CAN give bladder infections - and then if left untreated long enough - kidney infections as well. Automatically and with ALL women, tiny bits of bacteria from fecal matter get pushed into the vagina and eurethra as intercourse occurs. Nothing can stop that and nothing can change that, although the degree that it happens will very based on positions. It happens no matter what if you engage in just vaginal intercourse, even if nothing anal-related has occurred. SO, all doctors advise that almost immediately after vaginal intercourse the woman should urinate to help flush out bacteria from the eurethra so it does not make it's way into the bladder. Intercourse is one of the main ways women get baldder infections. urinating right afterwards is one of the best ways to avoid infections.
Kidney infections occur typically if bladder infections have been left untreated for too long. The first complication is usually the bladder infection.
To be honest, it's wise for women to urinate after manual insertions into the vagina as well, for the same reason. The 3 holes are close together, and bacteria from the anus can pass easily to the vulva to move up the eurethra. All it takes is a bit of moving action "down there".
5) Someone above alluded to some extent that you should not put a penis into an anus and then insert it into the vagina.
Absolutely correct.
If vaginal intercourse alone can spread bacteria to parts of the vulva (vaginal opening, eurethral opening, etc.), then you can imagine what vaginal intercourse following anal intercourse can do.
the guys should scrub very very well if that is going to occur, but I don't think it would be recommended.
Best to stick to doing vaginal intercourse first, THEN anal intercourse. Teh gusy should of course try to urinate afterward and even wash up well after. Having said that, men as far less prone to bacterial infections/blader infections than women, but still best to be safe rather than sorry.
6) to the same effect - and for the same reasons as above - if a finger is being used to do anal activities, it should NOT be the same finger used for inserting into any part of the vulva/vagina, nor into the mouth.
Bladder infections etc. will occur, and if into the mouth, well we've all heard of things like ecoli, right? In extreme cases ecoli can cause kidney failure. If you wash veggies to help get rid of bacteria from manure, shouldn't we think about the same preventative measures and consequences for anal activities...?
Bottom line is, if engaging in anything anal, wash well before and afterweards. BOTH partners. And make sure you're urinating periodically, particularly when you're "all done".
On a personal note, I love recieving analingis and my husband loves to give it. I do not, however, kiss my husband after he has performed it on me unless he brushes his teeth and mouthwashes - in fact I insist he does so for his own sake. And if he performs any anal activity on me (or vaginal activity beyond intercourse, such as cunnilingis) then we make sure I am newly clean to the point of being sterile in that area.
I think many women would benefit greatly from allowing the men in their lives to perform analingis on them, but they have to feel emotionally comfortable with it, clean etc. It can do a lot to keep your vagina turned on/lubricated for a MUCH longer time, and allow vaginal intercourse to go on much much longer.
A tiny bit of fingertip insertion would also provide a lot of pleasure for women if they weren't self-conscious about things, BUT their partners should always make sure the finger used is clean and lubricated in some way before insertion.
Many women will not want it inserted all the way in unless they are at a certain point of arousal, but even then they likely will only feel good about a small bit of fingertip.
In contrast, I would say that most women - even those who like to recieve analingis and manual-anal activities - will not be up for returning the favour to their male partners. And most women are not up for penile penetration of the anus - it is a very difficult act to achieve comfortably, let alone enjoyably. I wish a gay man would write a book one day so they can guide heterosexuals as to how to manage that "end" of things (no pun intended) better, should they decide to go for it.