Okay Nina
That you want to be permanently gaping no matter what is insanely hot!
So I dare you to buy a squash - the biggest one you think you have a realistic chance of fitting inside you. You can buy bigger and bigger as you get better!
When at home you have a choice. Either buy a condom to put on the squash and use KY jelly, or as I do, use vaseline without a condom - with enough lube anything will fit inside you!
One of the worst ways to get big things in your ass is to do it doggy. So, I want you to get a mirror and place it on the floor. Put the squash on the floor sitting up, get it and your ass really lubed up, and squat down over it. Watch yourself slowly sitting down on it. Now, gently and slowly let the squash take your weight whilst watching in the mirror.
The first time you do this you might get none of it in you. I dare you though to do this every day for a week and report back on how much you achieve. With effort and care, each time putting more and more of your body weight into it, more and more will stretch your ring out. The best thing is watching your own arsehole getting ruined
The other option is to do it on your back with your legs up, but it's harder to get up enough pressure on your ring.
If you are really really serious about gaping wide I do have a few more permanent options...