The ultimate 5th position, not showed at the picture, is the head of the mic inside the mouththe legend says that the origin of the 4th position was to avoid feedback while using this in combination with a high power reggae sounsystem in jamaica in the 1970's, and that some rappers took it over because they thought it looks cool.
If it's true i don't know, but i do know that that trick works, i did it myself in such a situation while i was a dj, otherwise the mic was not usable because of the feedback loop. But off course you block a lot of the sound of your voice also.
Or as the kids say: FAFO.