I think a lot of it has to do with how you are wired (physically and mentally) and also the other person that you are with.
My journey to anal sex was interesting as I thought I was straight for my teenage years and fucked women, then discovered men. My first time with a guy I bottomed and it was so bad and painful (he was inexperienced, hasty and very drunk) that I didn't really bottom again for a couple of years after that apart from a few half hearted attempts. Then I had a long term relationship with a very versatile boyfriend who was patient and encouraging and next thing you know we were flip flopping with wild abandon (he, i should add, was a very large boy at 9.5 - 10 inches when most turned on) After I enjoyed bottoming so much with someone so large I was less afraid of bottoming, learned to relax more and now love it.
While I am still versatile I find that the men I am attracted to (older, hairy, beards/stubble, rugged) tend to be tops and/or are more interested in fucking me (slim, cute, younger, boyish) If I am with someone closer to me in age and closer to my own body size I am much more likely to take a more dominant role and want to fuck them.
So in short I think I was wired to be versatile, but had to learn how to enjoy bottoming (which I think is by and large the case with most people)
ps I will top or bottom or be versatile for you CuteGuyLondon :biggrin1: