I just gave the 8 foot bullwhip that I’m working on a good rolling between two boards. this smooths out the bullwhip. One thing that I’ve learned about rolling whips is that it’s hard to do it with just two boards.
Ron Edwards suggests putting a bit of rosin on the boards. I haven’t tried that, but I imagine it makes it a bit easier. David Morgan suggests wrapping the boards in butcher paper. That is what I am currently doing and it makes a world of difference!