Vibrational control is an open-loop control technique that uses zero mean parametric vibrations for shaping the response of a linear or nonlinear dynamical system. Several theoretical results are available, based on averaging techniques, assuring the possibility of modifying the equilibrium properties of a system. For nonlinear systems, computational difficulties arise and theoretical results cannot easily be applied. In this note, the stationary behavior of a class of nonlinear systems vibrationally controlled by AP-forcing is investigated. A practical formula linking the amplitude and the frequency of the vibration and the amplitude of the steady-state oscillation in the controlled variable is obtained. As test cases, the well-known Rayleigh equation, a catalytic reactor equation, and the phase locked loop equation are considered.