5th grade, first I discoved how 2 crack my knuckles/toes, then my neck, then my back.

I just discovered, If I lay flat on my stomach and bring my leg to my side and lift up, my lower back will crack. Try it on both sides

What I do is I lay on either my right or left side and place the
palm of my hand on my lower back. Then I push down with
my hand and turn over on to my stomach.