I believe red rice is supposed to decrease sex drive or cause ED?

Miscellany said:

I believe red rice is supposed to decrease sex drive or cause ED?

That would certainly explain the sister's insistence that they scarf it down, wouldn't it?

I only know of the red rice being used when a girl of the family got her first period, as per the translation note.

I guess this is her way of showing she's proud of Yuuto or something.