There is not much spiritual meaning in keeping open to the Mother if you withhold your surrender. Self-giving or surrender is demanded of those who practise this Yoga, because without such a progressive surrender of the being it is quite impossible to get anywhere near the goal. To keep open means to call in her Force to work in you, and if you do not surrender to it, it amounts to not allowing the Force to work in you at all or else only on condition that it will work in the way you want and not in its own way which is the way of the Divine Truth.
Ref: The Mother with Letters on The Mother