> I mean, practically speaking, how do you control how long you spend asleep?
No idea.
I rarely if ever "sleep" when napping. That is totally fine though, because lying down with eyes closed, sleepmask and headphones with something soothing on, is enough to make me feel better.
> then spend the next 10 minutes waiting to fall asleep
Stop doing that. You are stressing yourself trying to reach a (the wrong?) goal.
> that awful wrenching feeling of being forced awake when you haven't had enough sleep
No idea.
I rarely if ever "sleep" when napping. That is totally fine though, because lying down with eyes closed, sleepmask and headphones with something soothing on, is enough to make me feel better.
> then spend the next 10 minutes waiting to fall asleep
Stop doing that. You are stressing yourself trying to reach a (the wrong?) goal.
> that awful wrenching feeling of being forced awake when you haven't had enough sleep
On days like this i take several naps.
Hope this helps.