Breathing is important, as you may already know. Some people even breathe several times a day. Breath control is vitally important when it comes to beatboxing, and this sound is one of the most commonly used inward sounds. Inward sounds are, as you can guess from the name, sounds that are done inwards meaning you can take a breath at the same time.

To make the sound

1 - Put your tongue on the top of your mouth
2 - Suck a little to build up pressure on the left side of your tongue
3 - Snap your tongue away from the side of your mouth to get the K sound - the "shh" afterwards comes from the air you inhale

This sound can take a while to get the hang of because it's commonly the first inward sound you'll learn, but it's very versatile and probably the most widely used inward sound.

Peace, love, and a breath of fresh air

-FT