Stuffing

How quickly can my stomach expand if I still drink one liter after eating on a full stomach? How much more can I do one week later?

"It depends"

If you're already quite stuffing yourself during normal eating, then I would assume not much will happen. If that's your initial starting point, then maybe you can drink a liter more than you can do now?

There's only one way: let's try and find out.
Keep it fun and keep it safe - get used to the "full" felling and go a bit further every time. Don't expect the capacity growth too quickly, or you might get sick and loose the fun in it.
I love to reach that point where I can't suck in the belly any more - how far do you go while it's still enjoyable?

I think I'm already filling myself up a lot. The question is how quickly will my stomach expand if I drink another liter every day after eating?

If that liter gets you to the "my belly feels stretched, I can't fit more" feeling, then it will definitively expand your stomach and increase your capacity.

If you ate little and that additional liter afterwards does not make you stuffed, then I doubt it will change your capacity over time.

ich denke, wenn du das jeden tag machst das man schon in 1 - 2 monaten mehr hineinpasst. wichtig ist dern magen wenn er voll ist gut zu massieren, dadurch wird die verdauung angeregt und es passt schneller wieder was rein.

i think water and liquid in general is less effective at stretching your stomach than just eating more food. i don't know the science behind this, but i suspect it is both absorbed into what you've already eaten, and is also absorbed into the body much more quickly than solid food.

so my advice is not to play with trying to keep a jug of water down, just push yourself to shovel in a few more mouthfuls!