People

You know, there is a whole subset of the internet devoted to people... Men, actually... males... that attempt to launch stick tailed fireworks by initially holding the stick in their gluteal cleft.  Gluteus Maximus, specifically.

They hold the stick in their butt cheek (just their cheeks if they are lucky, but ... yeah... they hold it there too) and a buddy lights the fuse for them.

Alcohol is involved.

There are LOTS of these online.  Video.  The results are the same.  It never ends well.

The fireworks rocket propellants starts first.  The sparks from the fuse alone is enough to cause a clenching, and that clenching is strong enough to hold the works in place.  4 seconds of blasting blackpowder style propellant.  Which is bad enough.  Then... the main charge goes BANG!

Yet, there is some drunk person out there, right now.  This genius has even SEEN all the videos and KNOWS the consequences.  No, he thinks, this male... no, I know what they all did wrong and it will be different when I do it in front of my buddies and their phone cams this 4th.

This one is the first I ever saw, and still may be the best.  There are dozens more.