What is the English translation of the French expression faire la courte echelle?

"faire la courte échelle" means literally that you are helping someone to reach an object placed too high. You lock your hands by the fingers and let your arms down; then the other person puts one foot on your locked hands and use them as a makeshift ladder ("échelle" in French) to reach the object.

The figurative meaning is to help someone to get something that would be impossible or hard to get without your help.