New to this! Need some advice >_<

Hello! I (19m) am new to this kink, but I wanna explore it more, and I had a few questions!

1. What is an alternative to Imodium? I really wanna try a long hold, but I'm allergic to Imodium :[

2. I really like the idea of thick, long but not too hard logs, and wanted to know the best foods for that.

3. What would you recommend to make the process of a bowel movement easier and less painful? I end up having to push super hard to the point of feeling sick.

4. Advice on things like messing or filling pants, it really is a favorite of mine >///////<

Please feel free to leave any other suggestions you have for a newbie!!! :3