Add a custom key/button
I've played it too to understand.
Doing the same would be ok; not the most elegant solution, but good enough for me.
I'd prefer exploit the "quick_ping" button, but I dont know how yet.
I use ESDF for movement, and almost all other key is bind to something (mapping things, wireframe, visleaves, infos, framerate, hide portalgun, add portalgun, noclip, reload, loadgame etc.) so I would be angry if someone deletes/overwrites any (since I cant remember all of those)
I assume it until I prove it wrong.
Anyway, I was quite happy with your methond, until I discovered that you cannot "duck" after a jump...
Honestly I wanted to check your map back again, but I can't now, so I'm not sure it happesn there too.
that's a big issue for me 
@DaMaGepy
I'd like to avoid it. felix's method almost worked!
Little bit of a topic shift here, but stil related. If I am trying to make a map pack with custom controls used throughout, such as swap weapon, revert to previous, flashlight, etc.... Would it be just easier to make it as a mod?
With a mod I might also be able to use custom scene files and bik videos as well which would be nice.
But mainly I'm asking because as said, you can't crouch during a jump or while falling, and I have more than 1 binding.
(I know it sounds better to use in the portal 1 engine, but I'd really like to have all the portal 2 related entities, plus the portal 2 style, physics engine, and models/textures).
Aperture Science: We do our science asbestos we can!
to be precise, you can crouch while falling, if you have not jumped, like by running off a cliff.
I think it's better to keep it a map as much as possible, to be workshop compatible.
Well either way I'd probably have to use more bindings than just crouch, because I need at least 4 bindings. Workshop compatibility isn't an issue, i could just post a map demo on the workshop and have it say at the end that there is a full download link in the description with a full instruction area for noobs. The main issue is whether or not I should release it as a mod I guess, because a small map pack would be enough to fill a mod. Maybe just classify it as a mini mod? I don't know.
Aperture Science: We do our science asbestos we can!
workshop's main advantage is smooth/easy installation.
I'd go for a mod if it really adds something.
I followed the instructions exactly but for some reason my game refuses to acknowledge bindings to entities.
It just keeps saying "bind <key> [command] : attach a command to a key"
was there an update that changed this or something?
Did you correctly insert the "quotes" around the command you were trying to bind?
Aperture Science: We do our science asbestos we can!