Ha ha ha oh WOW! There is a detailed sex guide over here which includes Magnezone's button panel as well, but it is not for the faint of heart.
Most of the characters were designed to have mostly intuitive rules the player can figure out! "Grovyle likes when I rub their feet", "Buizel cums too quickly if I touch their genitals". Magnezone was designed to be incredibly esoteric and convoluted! But more or less you want to deactivate all the lights, see what happens to the remaining lights, and use that information to interact with their rear panel in different ways.