Used when someone must depend on something else because other options have failed or are unavailable. With no jobs available, he had to throw back on his family's help.
Pro Tip 2/3
Last Resort
It implies using a final available option when in a challenging situation. Stranded in the airport, she had to throw back on her limited knowledge of French to communicate.
Pro Tip 3/3
Under Pressure
Often indicates a person is under stress or in a difficult position when seeking help. When the project failed, the team had to throw back on their mentor's expertise.