Does anyone know at what point of your cycle EWCM is supposed to happen.... ? Before, during or after O?

I didn't realise that Cranberry was good for conceiving girls so I'm off to get some today... I know its good for everything else female so thats just a bonus!! I recently saw a naturopath who put me on some Magnesium and Potassium tablets so I've cut back on the Potassium until I fall pregnant and see what happens!!