How to be a better bottom?

Hey so I’ve been told my ass is fat! Which it definitely is but my only problem is I can’t take big dick that well!!! I’ve taken a few in the past and tapped out I wanna be a power bottom and start taking dick on the regular where it is second nature to me! The times I have been fucked it hurts but I love the thought of it which turns me on! Do butt plugs work? How can I get better at taking dick like a champ?