Does anyone know any guides for drawing soft squished things

[extremelydevious]

Im looking for a guide or tutorial or the name of a book even that will help me draw soft/ squished things, the rules for that, and etc, i need it to help me draw certain details in vore art. for example;
A butt while sitting,
Large butthole, especially when its overlapping the thighs
Boobs (they get pressed on a lot of stuff)
general contact with pudgy things (like how in certain poses the gut may press upon the thighs and etc)


I dont even really know how to generally describe what it is im looking for.

its to do with not just lining it in, but also how to do the shading/coloring to make round/lumpy things or stretched out things look still look squishy and proper

[passage]

Modeseven made one a while ago on tumblr (nitro_titan on this website I think)

[Dekkard2]

Here's a few I favorited a while ago

https://www.deviantart.com/lordstormcal ... -472974172
https://www.deviantart.com/muhboobz/art ... -444388799