one at a time for maximum delta-P

Fun fact, your body uses only one nostril at a time and closes the other.
It switches throughout the day and keeps nostrils moists.

https://en.wikipedia.org/wiki/Nasal_cycle

I'm learning that there are people who blow their nose with both nostrils at the same time.

This feels like when I discovered that there are people who wipe their butts from behind.

I can't blow my nose at all. Some weird mental block. I sniffle incessantly and drive everyone nuts instead.

One at the time.

Both at once like a turbo engine. My sinuses are huge due to a lifetime of allergies

One at a time. I also can focus the energy on either the more front of the nose or the back of the nose towards the throat. I wish I could explain how but I cannot and it would be good if my kids could do it because it can help a lot.

I don’t really blow it, I just pick and flick

Both at once, hard enough to shoot boogers right through the tissue with a satisfying thwack. Bonus points if the neighbors move out because of the noise

Both

Rapid vacillation between the two.

Both

First right, then left. Very gentle, as overpressure is bad.

Snot rockets, marathoner style.

Very carefully.

Naah for some reason I find it incredibly disgusting. Instead, I scream till it gets out.

Depends on what is clogged

Draw as hard as i can so it all goes to mouth and spit it out. I thought that's the only way :D

One at a time. Cant get enough pressure to do both at once.