NB! It seems this console command is not compatible with CS2.
Command Profile

+MOVEDOWN

CS:GO

This command only works in noclip mode and in demos: this command will make you (or your free-roam camera in demos) move downwards. Use -movedown to stop moving downwards.

Syntax
+movedown

Description

This command only works in noclip mode and in demos: this command will make you (or your free-roam camera in demos) move downwards. Use -movedown to stop moving downwards.

Syntax And Arguments

+movedown