In this diagram, it would be ‘lefting.’

When people challenge in seriousness or jest, often it’s because they’re scared the boat will sink with the person on the other end drowning.
A.K.A. teeter-totter, seesaw, point-counterpoint,
thesis-antithesis, cyclone-anticyclone (i.e. winding & unwinding air to alleviate ‘dizzying’ from centripetal force),
yin & yang, Tory-Labour, Rep-Dem, red-blue, conserv-lib,
protagonist-antagonist, West-East, acid-alkaline, etc.
It’s ‘chemistry’ where electrons spin out
& are attached or rejected by + & – charges.