well obviously if your feminizing a plant (forcing it to produce pollen sacks as opposed to pistils via ethelyne inhibition aka tiresias mist) it has to be a female so that when you take pollen from the XX male that youve made produce pollen and cross it to the XX female you get all XX seeds and with no Y in the picture (XY) you get all girls, does that make sense? so spray it once you flip to flower right when you flip is what it means.
you cant feminize a male. thats just a sex reversal and youd need ethephon.