When i was 16....

...I think I suddenly discovered how erotic my asshole was and become somewhat obsessed with it but I was slow to pick up on lots of stuff I don't really think it is a physical issue mostly after all pooping gives an essentially sensual pleasure from infancy it's a question of how familiar a boy has become with his various erogenous zones if the anus as a source of the type of pleasure he gets from his penis is a novelty for him it might take quite a while for him to get his head around the idea of a man fucking him but and perhaps there is some age, doubtless vastly different for different boys, below which he could not get his head around it at all. But those are issues relating to the development of sexuality, not physical capability. As for enjoying it, the first time I got fucked (though I was no boy at that point) it was much more painful than I expected it to be, and I had done plenty of anal play. I don't think that is an uncommon experience at any age. Again, that has to do not with age but with the fact that imagining being fucked and actually being fucked are just two different things, and that can take getting used to. I think any boy interested enough to do it can enjoy it, though maybe not the first time unless his partner is very skilled and patient. If a boy is not interested in doing it but does it anyway, for whatever reason, of course he may enjoy it less or not at all, though interested boys may feign a lack of interest since there remains a stigma attached to wanting to be fucked. hugzu ;-p