This is an action like crouching, but instead of crouching you lay down. This can be used by everyone for moving discreetly, or taking in tactical position. This has been suggested before, but the problem was that the game has no animations for it. I searched a while on Mixamo and found lots of stuff the devs can use.
#Add firing position to the game.
slate sentinel
Another advantage of Mixamo is that you don't have to credit them
Example of Firing position
unborn quiver
Like the many times it has been brought up in the older suggestions system, AND the few times in the new suggestions now... the game currently does not have the animations for this. It is something that has been considered though and might be fun to add in.
The suggestions normally use the term "prone position", since that is the typical name of it.
Use of a tool like the above has limits which ultimately still results in work for the devs + balance considerations (assuming it even is compatible with the WB model, which is slightly less 'generic' than it may seem).