Rear window switches for rolling down don't work easily
 

rolling up they work fine. rolling down, sometimes I have to press with 100000000 pounds of pressure

sometimes I have to push just right.

rolling up works 100% of the time, with little effort

Any ideas why this happens?

no one?

Sometimes threads get buried, sorry it happened to you.

Give this thread a read, if cleaning the contacts doesn't solve the problem, you can find the complete switch assemblies fairly cheap online.

https://www.chevyhhr.net/forums/problems-service-repairs-42/power-window-switch-46384/

Sounds like the contacts in the switch. I would replace the switch, and not even try cleaning the contacts, which would probably only be a temporary fix.

Could be the wording. The amount of pressure on a switch does not matter to the switch.

It does not matter how hard you kick a brick wall the wall still wins.