As per the title can creatures with gaze attacks choose to disactivate them? Or does it have to specify in the description
In 3.5, creatures with gaze attack could suppress it, but in Pathfinder, it seems that the only solution for the creature is to veil its eyes to prevent the gaze attack.
Gaze attacks can affect ethereal opponents. A creature is immune to gaze attacks of others of its kind unless otherwise noted. Allies of a creature with a gaze attack might be affected. All the creature's allies are considered to be averting their eyes from the creature with the gaze attack, and have a 50% chance to not need to make a saving throw against the gaze attack each round. The creature can also veil its eyes, thus negating its gaze ability.
That is how they are deactivated (unless otherwise noted in the monsters description).