Because you were doing it wrong. Go to a doctor.
Cracking knuckles sound like cracking knuckles
The sound of knuckles cracking is caused by gas bubbles rapidly collapsing in the synovial fluid in the joints. This release of gas creates a popping or cracking sound.
Air-crafts make a sonic boom known as a "boom'sound or 'whip cracking' (cracking) sound.
This is absolutely normal, and happens because the penis acts like a piston pushing the air in and out. It is more likely if you have intercourse incertain positions, for example with your bottom up in the air. I some countries some women learn to control their muscles so well that they can play tunes.
knucklephobia
It makes like a cracking noise
The sound is caused by static electricity.
The Slap Stick
Break or cause to break suddenly and completely, typically with a sharp cracking sound.Emit a sudden, sharp cracking sound
Trees can make cracking sounds due to a phenomenon called "wind-induced stem breakage" which occurs when strong winds bend the tree causing internal stresses that lead to cracking. Another reason can be the expansion and contraction of the tree's sapwood as it absorbs or loses water, especially during temperature changes, which can cause the wood to crack.
A horses loud neighing to another, (usually a stallions call), is sometimes referred to as a bugle.
No, you don't get arthritus from cracking your knucles. You're not actually cracking it, you are just "poping" your bones together