Directly underneath the chin (above the Adam's apple) is where I've experienced more success. I found pretightening the noose before going down on it helps speed up the trip to unconsciousness. I also put a towel around the front of my neck for comfort and to apply more pressure on the cartoids to the left and right of the Adam's apple. When I go to actually follow through with my suicide, I'm shaving my head and beard to avoid any uncomfortable hair pulling from the noose.