Repeat ad infinitum.
Somehow I don't think you've thought your cunning plan all the way through.
^Not possible. The mother's nutrients isn't as infinite as the sake inside Suika's gourd.
But isn't the nutrient drain only applicable when the mother has more than one stalk on her head at any given time (e.g. gang-raped by a bunch of Alices)? This Reimu has one stalk each time, so I don't think it's enough to drain her completely. Yet.
If I'm wrong then I apologize.
it is Multiple stalks, even if only one at a time. The mother will run out of nutrients unless She eats some food. That'll be right around the time that the entire family yells at Marisa for not being able to feed them properly.