First time trying Anal

Okay so my boyfriend has been talking to me about trying anal for a few weeks now. Neither of us have ever tried it before and we're both kind of curious but I've been scared about it bc it's just really something not many people talk about where I'm from. And anything could happen. He wants to try it tomorrow when I go over to his house & I'm down but I just want to know kind of what to expect... Any advice or suggestions??