Need advice! Sexual Content!?

Last night my boyfriend and I got home from a party, he was a little drunk but not too much, we started to mess around and as I was giving him oral he kept pushing my hand off his balls and closer to his *** (something he has never done. Usually he would say it's gross if I even joked about touching his anus) when I finally just started fingering him a little he seemed to really enjoy it. I just dont know where it came from and what to do about it. - do I do it next time? Or assume he was just drunk. Also to any other women, how deep do you put your finger in him? I'm just shocked that he even wanted that..it's fine with me i guess I just need tips.