It seems that many here do not train themselves.
Theory theory, but as men and having dimensions and weight greater than Sister24, try to keep ~ 1500 ml. You'll see what a large dimensions will be belly, even if at 1000 ml your belly was completely flat. When the border was exceeded ~ 1000 ml, visually volume increases very sharply and disproportionately.
It will be very similar to Ayla, Clare or Rachael in those videos, where they hold up to 1300 ml.
Logically can imagine what a huge volume of visible belly must be at 2000 ml. But such volume don't have Sister 24. She almost looks natural in the abdominal area.