I have had much trouble with gourds slipping off my lap or the table while working on them.  I have come up with the solution quite by accident.  I bought a roll of shelf liner for our new house.  It is soft and cushy.  It sticks to the shelf with no adhesives.  It is made by Rubbermaid.  Nothing, and I mean nothing, slips or slides on the surface it covers.

I had a piece of this liner laying on my counter.  I sat a gourd on it. I was attempting to mix some paints and the gourd was too close.  I tried pushing it out of the way and it didn't move.  In fact, I pushed it over onto its side.  I knew right then this is what I needed to use on my lap.

Then I got the idea to glue some of the liner on a pair of thin work/gardening gloves.  My gourds never slip out of my grip while working on them.