Not being an expert in fisting. But I have read that Crisco works but is rather discusting. It is a lard based baking stuff with the consistance of Grease. I know that back in the 70's thats what Fisters would use.

Yuk!

Wasnt there a scene in te "last tango in Paris" concerning A large amount of Butter.

Dont remember what they used it for.