[hammock]

The guy in the grandparent YouTube video suggests shaking the coin in a closed hand (or better, a box) to randomize the starting side and then transferring it unseen to someone else to flip it

Craps is also brought to mind where the dice have to bump the back wall

[roccomathijn]

Let's abandon coin flipping in favour of coin shaking then

[dotancohen]

It's a shake and then a flip. Put your hand on your hip and bend your knees in tight.