That's not c-glitching, but it's shooting while crouched.
I'll quote a post of darfy.
Also everyone make sure you don't confuse the two terms "crouching" and "crouch glitching" which are two totally different things. Crouch glitching is still disallowed as clearly stated in the server rules.
Denied.On edit :
C-Glitching
Unlike fast switching after firing a weapon the player is unable to move for roughly 0.5-1 second. However, crouch switching is different. After a player fires a weapon when crouched and changes weapon to sprint there is no delay before that they have to wait before they can run again. This means that players can stack up a lot of fast movements and shots in a very very small period of time. Players can then spam a large amount of imprecise shots in a small amount of time and manage to successfully hit their target. This kind of glitch removes any of the skill elements of having to aim precisely and pick and choose shots carefully.
Due to the large amount of fast movement in a short period of time this also adds a lot of desync between players. This is not so bad when it is two low ping players fighting each other but when two high ping players are fighting each other this causes A LOT of desync between the clients making it harder to fight.