I can't get the seduction for the small butterfly to work. It seems to be inconsistent with when the correct action is supposed to work.
Some girls have different sweet spots based on their seduction phase. For example, mommyfly's initial sweet spot on wings disappears after she loses the cloth on her chest. It changes from girl to girl so you'll need to explore how they react and not just press the same skill until you win. Though, this can work too in some cases.