teeter-totter
Definitions
A long board balanced on a central support, on which two people sit and alternately lift each other by pushing off the ground.
To move unsteadily or sway back and forth as if about to fall.
Examples
The children took turns sitting on each end of the teeter-totter at the local park.
The economy seems to teeter-totter between growth and recession as market conditions shift.
She felt her emotions teeter-totter between excitement and anxiety as she prepared for her first day of work.