Anal fingering!

So, me and my boyfriend were having really good sex. I was on top of him leaning on his chest and he was the one stroking me while I was rubbing my clit also. We were super into it, I was about to have an orgasm and he started fingering my ass out of nowhere. It was the best feeling ever and I sure did have the best orgasm EVER! Do you do this often? Do you like it or not?