I agree with Sammy73.
I had the same issues until I met a lady that was like minded.
My recommendations are based on my long learning curve.
1. Discuss it and only proceed if you both agree.
2. Hygene - both freshly showered.
3. Fasting - My Lady will either fast or eat only very light meals before we know we are going to have anal sex. It's no good going in after a burning hot curry and six pints of Lager.
4. Lots of foreplay - we use verbal roleplay to wind each other up to a fever pitch. Using your fingers then move onto a well lubed but plug before trying penetration. I also use a clitoris vibrator on her clit to help her get in the mood.
5. The Lube: We prefer a water based product called ID Glide which is available from must adult high street or online shops. Some people prefer a silicoln based lube but we just didnt get on with it.
6. The penetration position: We use the foetal or doggy position as they are both ok for us.
7. Dount Double dip: Wear a condom at all times and dont be tempted to "double dip" i.e. Penetrating the anus then the vagina (assumption here) repeatedly. We did this bare back once and regreted it for 2-3 weeks afterwards resulting in big problems for me with a very sore penis.
Hope this helps you
Does your friend know how you feel? Does he feel the same way?
Are you asking about how to approach your friend to have sex with him, or do you want to know how to do anal sex?