How do I make them stop wobbling? I might spill my coffee...?!

Our neighbor recently invited me and the missus over for coffee at one of the finest coffeehouses in town. It was perfect- there we were in our finest clothing, there was a wonderful little jazz ensemble playing. The piano solo still resonates in my mind. However, we were dismayed to find that the place was full, and we had no chairs. Mr. and Mrs. Vane waved at us, but there were no chairs. So I ordered my two twin sons to get on all fours (they're fourteen) and the missus and I sat on their backs. I'm typing this from my laptop. They're wobbling now, how do I make them stop?