No need to bound anything to mouse, just add another stance, just one - lying with your head stuck up. Upvoted.

I like this idea. Its clunky having to hold ctrl and my up stance key... Not to mention takes longer to do and can't get down quick enough to avoid getting a bullet between the eyes.

you can use freelook and move your head up, this is not neccessary

Negative.

keragon, what do you mean with negative? using freelook works just fine

press stance up key, then press stance down key. problem solved.

dr death, using freelook doesn't allow you to actually move your view position up, only the way the camera points. you're an idiot.

john cage, why dont you stop thinking you are right and try it by yourself?

when you do it, tell me who is the idiot.

Dr_Death

Negative. Your solution does not work as described.

then there must be some mistake, when you move your camera up you would be able to see behind something blocking you, of course, it shouldn't be 19 feets above your head, and you must be in first person view, still, i think this suggestion is useless

Dr Death, thanks for the suggestion but freelooking does very close to nothing.

Use this screenshot for reference:
http://i.imgur.com/9zxaiNL.jpg
If I lie down here I won't even nearly be able to see across the wall.
In reality I would simply do a slight “push-up” in order to just be able to peek above the wall and the same applies to tall grass which is about that height. Now I’m able to see my greatest enemy – that bastardly tree I’m looking at over there.
In ARMA what I have to do is change my entire stance from the prone stance into the sitting stance. While this works from a first-person perspective it results in an absolutely ridiculous animation in third-person. It makes players seem like dying fishes wildly swinging their lower bodies around from behind them in the prone position to in front of themselves in the sitting position and just really sucks. Especially if the sitting stance is removed from adjusting completely like I’ve suggested elsewhere this suggestion would be relevant since you’d be switching between prone and low crouch directly as there’s no intermediate. It could cause some similar animation problems.
Check this video out (Youtube, 19 secs):
http://www.youtube.com/watch?v=0CQ6KjTWuEk
I’m trying to see the tree and currently this seems to be the only way. As you can tell the third-person animation is ridiculous instead of simply raising the upper part of your body to peek over it. It also moves you forward as you can tell near the end when I have to crawl back.

People are going to want to peek over short obstacles such as these stone walls or medium-size grass and then the only solution is doing what you see in the video and they're gonna do it. Wouldn't wanna get on a server where all the players are lying about in the grass doing that now would you? Bit of an immersion breaker, isn’t it?

Moving your head on freelook would mostly work when crouched on standing up, for doing a push up on that case, maybe i would suggest to bind "step over" to "peak over your head" or over a corner

Alternatively to a "stick up" command a high prone stance would also be OK IMO.

Anything that gets us a bit higher without having to sit up.

This article from Dyslexi covering basic controls in ARMA III should clarify the issue somewhat. I draw your attention to the section titled "Default Stances" and how incremental postures go beyond just standing, kneeling, and prone.

http://dslyecxi.com/arma-3/arma3-alpha-controls/

Personally I found a keypad thumb-stick like that found on the Razor Nostromo to be invaluable to being able to adjust stance in small stages. OH and having a TrackIR for head movement goes a fair way as well ;)

Cheers

Alternate stances are already evenly spaced and quick to use, no need to complicate the system more.