Please find this reddit post lol
It is obviously bs, probably based on the idea that some exercise, like running, destroys RBCs. In running they are actually crushed between the bones of the feet and the ground. I'm sure cupping destroys a small number but it wouldn't be enough to make any significant difference in RBC.
Cupping is "reverse message" and unbelievably effective in an insanely short amount of time. I can cup my infraspinatus muscle for 3 minutes and instantly make it stop hurting and the next day it feels great. My PT also cups me on a regular basis and it works amazingly. The best cupping is done while sliding the cup around AND having the person move that muscle's joint, my PT is extremely good with them.