I'd like to try a peanut butter flavored IMBC. Any advice on how to add it to IMBC? Do I warm up the peanut butter so it's a little runny? Do I mix it with cream or something first? Or does it go in straight-up from the jar?

When I used it for SMBC, I just put it in straight from the jar. It took a lot of peanut butter, probably 1 1/2C. It was so YUMMY!!!!

I just add the peanut butter straight from the jar. I add a little at a time until I get the flavor I want. How much pb you need depends on how much icing you are mixing it into.