The sequential contact transformation technique is applied to the vibration-torsion-rotation polarizability tensor operator for a molecule containing a threefold symmetric internal rotor. Detailed discussions about various types of polarizability tensor operators end corresponding vibration-torsion-rotation transitions are presented. The formalism of the transformed polarizability tensor operator makes it possible to analyze various high-order vibration-torsion-rotation interactions and their effects as well as to determine the intensities of transitions between vibration-torsion-rotation states within the Raman spectrum of the molecule. As an example, the transition matrix elements of the transformed polarizability tensor operators are discussed for CH3OH-like molecules.