One. Always wear a condom with anal sex - the chances of infection are soooooooooooooooo high for both of you.
Two. This is from a preious post of mine:-
here's a little info that I hope helps the newer members of sexual discovery.
While a boy has 2 holes (bum hole and one in his willy) the one in his willy actaully has a valve which stops him from weeing when fully erect (yes there will be some clever lad out there who can do both). Kinda of like a train interchange - you switch the tracks and off it goes in another direction.
now a girl has 3!!! Bum hole (leads only to rectum - further on is the intestines - no link to reproductive system), urethra which connects to the bladder only - this is very narrow and you cannot accidentally put a willy into it phew and the vagina - which connects with the reproductive system.
The only sure fire way to avoid getting pregnant is to not have sex
even birth control is only around 98% 99% depending on your choice - some is less effective still.
If you are using condoms dont double bag - this can cause friction can increase the risk of splitting. Try to get condoms which contain nonoyxl-9 a spermicidal, or use a spermicidal lubricant.
Always follows the instructions carefully.
Never use oil based lube (baby oil, cooking oil, massage oil, any other oil) with condoms or caps - the oil perishes the rubber/latex.