Hi, hi, sorry to butt in, actual real life waist trainer here! If a corset is made properly, broken in safely, and properly laced, it actually doesn't cause any pain or breathing issues! I'm laced down to 24" from a natural 28" and I've worn a corset, laced closed completely, all day at a convention with no problems! Wearing corsets SAFELY and PROPERLY can actually improve posture, increase lung capacity, and help with weight loss! I'm by no means saying don't prompt this, in fact I'm super jazzed whenever I see anyone take an interest in corsetry no matter the reason, but continuing to spread misinformation about what is not only a hobby but one of my special interests makes my heart do a sad face :(
I wish you luck on getting your prompt filled, and encourage you to research corsetry further! <3