“Hey Shay! I was wondering if a blowjob after unplanned anal sex is sanitary? Cuz I just had an argument with a friend, and he seems to think that it’s fine (too much porn I think) while I disagreed. On another note, though safe sex is highly encouraged, when is it a high probability that a guy cums inside a girl in good old fashioned vaginal intercourse and she won’t get pregnant? Thanks!“
Ideally, even if the sex was unplanned, a condom should have been used (even if it’s just to protect the inside of the penis from bacteria) so you would peel off the anal condom before popping the penis into someone’s mouth. However, I suspect you’re talking about unprotected anal sex.
In this case it still, [and I did check this with Dr. Joannides, of The Guide to Getting it On] it’s not too big of a deal – the flora and fauna living in your ass are pretty much the same as the ones in your mouth, so you aren’t liable to catch anything terrible like an ecoli infection from putting a toy or penis in your mouth after recently enjoying it in your ass – though the concept often does put people off trying it.
In fact, even if you were putting a penis or a toy in your mouth after it had been in a partner’s ass you shouldn’t have any problems, so long as it’s a long-time partner – just like with rimming, it’s not really an issue – because two people who have been intimate together for a long time will share similar bacteria already.
Additionally, as I’ve mentioned when I’ve written about anal before, feces isn’t stored in the rectum until just before leaving it – so the area where your anal penetration is happening should be relatively poop-free. Besides that, if your anal sex is properly lubricated, the lubricant coating may discourage offensive particles from latching on – though you might want to give the item in question a quick wipe before putting it in your mouth. (And once again, you should be using a condom for safety – even if your only concern is a UTI.)
As for your other question – speaking ONLY to the risk of getting pregnant – the “safest” time to have vaginal sex is during your period because that is when you are least likely to have a fertilize-able egg floating around (though it has happened).
I would like to stress that you should always be using some form of birth control (ideally two or more) – the only people who try to time when they are most and least fertile are the people who are trying to get pregnant.
I hope that helps!