Yep. That's an example of the dev's illogical approach. Yet there were even more stupid decisions from his side.However, lesbian acts still count as a mating behavior.
Both female chara will lose their lust once they've done scissoring.
Do you remember the time when pregnant sex was not allowed, which made leveling female characters a pain in the ass?
And, if it was up to me, any sexual interactions with NPC should cost 0 lust. Also, female characters should spend lust at a lower rate than male ones.
And I am not even talking of the issue that the dev, from the very beginning, should have implemented a kind of crafting system, so that we could craft potions from the extracted liquids and give them to nephs to replenish their lust. Would that be too difficult a task?