Quantum Mechanics - A branch of physics providing a mathematical description of the dual particle-like and wave-like behavior and interaction of matter and energy. QM describes the time evolution of physical systems via a mathematical structure called the wave function. The wave function encapsulates the probability that the system is to be found in a given state at a given time. QM also allows one to calculate the effect of making measurements of properties by defining the effect of those measurements on the wave function. Cunnilingus - Eating pussy.