The perception of taste is remarkably complex, not only on the tongue but in organs throughout the body.
The idea that specific tastes are confined to certain areas of the tongue is a myth that “persists in the collective consciousness despite decades of research debunking it.” Also wrong: the notion that taste is limited to the mouth.
Causes less air pressure at the upper side, so the lower side pushes up, no?
And the upside down flying is simply due to gliding mechanics, no?
Nope. Read the link, it’s fascinating and complicated.
Not sure what you mean by this. But planes still generate lift when flying upside down. Wings with a symmetrical curve can also generate lift. Flat wings with no curve at all can also generate lift.
Pressure differences are definitely involved. That’s the only way air pushes against things, after all, so the fact that there is a lift force implies a pressure difference. However the cause of the pressure difference is rather complicated.