Anal tips

Okay so.. I have a tight butthole and my bf has a big D😅 and we both wanna try anal. I done it when I was 14 and at that time was no problem. But now I’m scared for some reason. I really want to try it. I know to make sure I have a bowel movement before, then shower and have condom and lube. But what else do I need to do to prepare?