An approach for introducing damping to the flexural vibration of rotating shafts is presented. The idea of the approach is simple and the implementation is novel. The idea is to introduce viscoelastic angular spring at the boundaries. The spring would stiffen up and damp out the bending fluctuation, and therefore would increase the frequency range of operation and alleviate the vibration amplitudes in the vicinity of resonance of the shaft. The idea is implemented by introducing carbon/polyurethane composite hyperboloid couplings at the boundaries (ends) of the shaft. The mathematical model of the coupling is developed and solved, using finite element, for the fundamental flexural natural frequency and associated loss factor. From the results, the merits and feasibility of applying the flexible coupling to alleviate the flexural vibration of rotating shafts are addressed.