text: Of course you already know you have to relax, but you have to be really ready too.  Ready for sex in general, not just anal.  Watch some videos or read a book, have a drink, flirt - get all worked up.  Then, start out with small toys or fingers (with plenty of lube - that cavity doesn't lube itself.)  Try moving up to larger toys during several sessions (if he knows what's good for him, he will be patient.)  You will know when you are ready for him.  I find it enjoyable but not all the time.  You have to want to.