You NEED to use, Fabric Paint.
ONLY fabric paint.
You can find it at craft stores.
These will not come off.
Sure, it may come in squeeze bottles. You just squeeze an amount onto a paper plate, and then use the stamper on it. Just like you would with any other paint.
You do not cut the bottle open.
You just squeeze out the amount you need... in order to dab the stamper in it.
The fine tip on the squeeze bottle is if you want to do fine detailed things.
Fabric paint, is easy to use. Just like any other paint.
Acrylic paint, will come off eventually.
Although it is water proof.
But it is not fabric paint.
Just use, fabric paint.
That is what it is for.
It is EASY. And specifically for fabric, painting.
I used fabric paint extensively and it is very easy.
You can use it with foam stampers, or with a brush or hand prints.
It is an easy medium.
Just like any other paint.