The trick is to "give a tool for 1-2 generations of customers" , and then they'll be fully dependent on the tool.
kids today cannot navigate without turn-by-turn. nobody looks at the map to get names of major streets, they just blindly follow the directions. I learned how to navigate as a kid just by being bored and staring out the window and being able to recognize things. Now, kids don't even look out the window as they keep their heads down and eyes glued to a screen.
No, many can feel it beforehand, and you notice it when you go to the bathroom before as well, as certain things change their properties slightly, it's not a "nothing" phase and then "floods out of your body".
It's borderline parody how little education there is for males when it comes to things like this.
You seem to forget that there is about a third of the day when shockingly enough a person is not conscious to feel blood leaking out of them. I mentioned staining furniture for a reason - I promise you that menstruation does not wait for you to wake up to start.