No, it is completely inappropriate. Incestuous and sexual content involving family members is not acceptable in society and goes against moral and ethical norms.
No. I've never heard of it in mainstream or popular story collections, and it sounds rather inappropriate and not something that would be widely popular in a proper literary or storytelling sense.
I have no idea about this so - called 'friends creampie mom story'. It doesn't sound like a common or proper story title. It could potentially be some kind of inappropriate or unrecognized fictional narrative.
Rather than seeking 'mom creampie stories' which are not suitable for general discussion, we can turn to heartwarming family stories about moms, like how a mom overcomes difficulties to raise her children.