Schematic depiction of the three torques involved in the quasi-stable pseudo-synchronous equilibrium of the planet-moon system. The tidal torque wherewith the moon is acting on the planet (solid blue line) is coupled with an opposite torque wherewith the planet is acting on the orbit of the moon (red curve). The negative tidal torque on the planet from the star (dashed blue line) is weakly dependent on the relative frequency. The vertical dotted line indicates the location where the tidal torques acting on the planet are equalised.