AAM

AAM is short for Advanced Attachment Method......and is usually considered to be a form of cheating. Many people mistakenly call this a glitch when in fact it is merely GMF file swapping.

It consists of using a different component mesh than the mesh intended to appear in the final result, and allows for stacking impossible ways in-game, as well as creating non-existing attachment points.

HX created a tutorial that explains how to perform it.