"fall back" is correct and usable in written English. It is typically used to mean "to retreat" or "to move back" - for example, "The soldiers had to fall back when the enemy advanced." It can also mean "to rely on something for support" - for example, "We can always fall back on our savings if something happens.".
They fall back.
Spring forward; fall back.
Fall back, baby.
Vazquez: Fall back.
Why did Japan fall back?
"Fight and fall back.
Mallon let his head fall back.
Thanks to Ludwig my first paper got accepted! The editor wrote me that my manuscript was well-written
Listya Utami K.
PhD Student in Biology, Bandung Institute of Technology, Indonesia