Chapter Two, The Breath, discusses breathing, breath support, relaxation, air compression, blowing exercises, the diaphragm, the lungs, inhaling and exhaling air, circular breathing, the relaxed throat, the glottis, warm-up exercises and excessive tension.
Really low sagging, like practically with your pants at your kneecaps is not in style right now, but sagging to show a little underwear, or the more PC term low rise is still in. Sagging is purely a thug influenced thing, dudes do this look like wannabe thugs that lost their belts in prison. I won't even lie.
This look started in prison because inmates were not allowed to wear belts, so their waist of the pants tended to fall low, sometimes halfway down the butt. This eventually made it to the general public because of former inmates and the thug wanna bes.