After a few hours of testing myself and with different headphones, I found the solution for the "it doesn't work" problem.
The problem is, your headphones aren't on tight enough, leading to sounds escaping outside and not into your ears. So I'm recommending not to use those folding type headphones. They're kinda too loose.
So the next time you try a dose, try pressing on your headphones or just find a way to kinda make a "suction" effect with your headphones and ears.
I swear, it just works.

