grrr. I just lost my whole post! Lucky for you, that means this will be the shortened version

I think your fears are natural and founded. It is going to hurt if there's no preparation/fun/foreplay/pleasure. Personally, I think it behooves your master to make your first experience most pleasurable and enjoyable. Being relaxed, having no fears, and taking it slow and sexy only helps create a future desire and willingness to accept forced anal. A bad first anal experience can ruin it for quite a while! And truth be told, it's possible to have the most earth shattering, body quivering, mind numbing orgasm from anal.

Lube helps, but isn't necessary... other natural lubricants created during foreplay sure can help a lot

I do disagree with Oz- if roughly taken, damage can occur. It has nothing to do with the size of bowel movement you've previously passed. Not only is the sphincter and internal organs meant to push out vs. receiving, you're also not clenching your sphincter when going the bathroom. Being too tense and having your body reject a rough anal experience most certainly can damage. Rough being the operative word.

Good luck to you and I hope it goes well! You're half way there because you're open to the idea. Perhaps just your first time or two doesn't need to be forced... have the opportunity to get all hot by the idea.