Wait, whats the difference between what you are looking for and those pics. As far as I know, they are the same position known as peshanko/pechanko suwari(literally meaning squashed sitting position) aka tonbi suwari, considered to be a childish sitting position and bad for the knee.
Trying to increase the angle at the knee is difficult so the pictures you posted are quite normal real life representations. This sitting position is usually only possible for flexible people (including children).
sockmuncher said:
if you like painful shit this is the wrong category
For adults/inflexible people, yes its quite painful, so it could possibly be painful shit hahaha.