Crisco is a vegetable oil that was used in the past often as a lubricant for fisting. Since it is oil based, it is not safe for condoms. Even latex gloves get dissolved after some time.
Nowadays water based lubricants or silicone based lubricants are mostly used. But some guys still prefer Crisco.
Crisco has a strong smell. I don’t like that. Of course I did try it as a lubricant, and it certainly works good. But it does not work for me, because it irritates my ass.
Sometimes water based lubricants (like J-Lube) don’t give enough lubrication (certainly after a long session). In that case using Crisco can provide the extra lubrication you need to enjoy your fisting session to the max.
Some guys start a fisting session with a bit of Crisco to get things started. And from there continue with J-Lube or silicone.
And you can mix J-Lube with Crisco with a blender. This certainly makes a great lubricant. But still smelly…