This expression just made me visualize stuff that made me giggle :)
You know how when you drink straight from the bottle, you have to raise the bottle to horizontal position and when it gets empty you turn your head back more and more and the bottle's bottom upward more and more? Yeah...
Meaning: drinking straight from a bottle
Now you see what I mean? The image of a dude playing a trumpet, and once in a while in a high point of the melody turns his head back and raises the trumpet upwards fully explains this expression.
I wonder if the first one to come up with this expression was indeed a trumpet player.
Anyway, amusing it is.