So i am sharing this is because not all type of girls are open to anal some has done it but are too afraid to do it with client so here is the guide
Step one
make your partner feel aroused suck her nipples/ kiss or etc (do not penetrate yet)

Step Two
start going down on her but from her behind, start kissing and carasing her back till her ass.

Step Three (if she your GF or if you Interested)
perform rimJob on her or eat her ass (make sure she uses Bidet every day instead of toilet paper) lick the anus first and slowly insert your tongue in and continuesly go deeper as time pass (dont go deep immediately if its her first time, wait 5 or 8 mins each)

Step 4
make sure your finger is well lubricated, try using lube products such as Durex aloe vera or any aloe vera base lube. super lubricate your pinky finger and start going in gently and slowly but not too slow. after a few mins move on to index and repeat lubricant process (if wanting to insert anything it must be heavily lubricated to prevent skin tear and blood loss. except for your tongue as it self lubricates) so goes for the middle,

step 5
you can start to stretch her ass slowly with 2 finger (slowly and gently) index and middle and make sure its lubricated again.

step 6
use a butt plug for beginner. it comes in 3 sizes for anal training. small, medium and large. lubricate them as always both the anus and buttplug.

Step 7
first insert the smallone and you can fuck her pussy, for 10 mins move on to the medium and for 30 mins move on to large. the reason why this takes long is to make sure her anus is completely relax and she does not show any sign of irritation or pain when insert dick inside

step 8
after using the buttplug. we can insert our dick if with condom please super duper heavily lubricate it as its rubber and can hurt the skin inside and its not soft silicon like dildo. if you clean feel free to cum inside she will feel closer to you and so would you to her

thats all for now and hope you guys enjoy a safe and fun anal sex life