I tend to use it mainly on LL61JZG, with very occasional use on the 2nd car (prob 1-2 times a month at most). In the second car I place it into a disabled badge holder and place it onto the dash. However, in the usual Lexus I tend to stick it on the windscreen....the surrounds of the permit have a plastic surround that allows the pass to stick to the windscreen.
After the PCN, I now place the pass in a second holder and place the pass on the dashboard.