Trying to replicate Inflation any help?

First off it's good being back on the site for the time being I thought it wasn't coming back but thankfully I was wrong.

Anyway over the past year I've been lokkilo for a way to recreate the Inflation in this scene : https://youtu.be/9OphTs4btaM

For me personally this is my favorite inflaInfl scene and the one that got me into the fetish (specifically ass) 

The Inflation seems so simple yet hard at the same time. On one hand it seems like a simple fat suit that's worn underneath the suit which seems simple enough but then what type of material is it? 

If anyone has any tips or advice please share.