Beating lash with Horde Orks:
Put one unit of Orks in front of the rest, 3/4" of an inch apart. Yes, stretch it across your entire army. Put all of your other units behind this unit in a similar formation.
It works against Chaos because Chaos is so small they can't spread out and hope to win. Chaos is elite, they MUST win at the main battle because there is only one battle for Chaos--where the cult marines are. Everything else supports these units. If you have a suboptimal Chaos army, you won't even make it this far--because you lose vs everyone. Chaos has to focus it's firepower against Orks because if you note you can't really lash anything but the guys in the back...who will just run forward next turn. So you have to destroy the orks, which really screws Chaos. If you have defilers, well Orks can kill AV12 pretty easily.
Beating lash with Mech Orks:
This ones pretty simple. Mount up. Find the spot you intend to assault. Zoom at it. Chaos will blow you up, wipe a couple units out, and lash two more. If you are facing sorceror lashes, put buggies between you and him so he can't see much. If you are facing
DP lashes, you can't really block
LOS so you need to kill them. If the sorc is by himself, zap him with kannons. Fortunately, ALL lash
DP are T5 with a 3+ save and so Orks can gun them down. I use fast buggies and shoota boyz mounted on trukks to shoot them down. Toss in a few kannons and
DP drop left and right.
Beating lash with Tau: (Mech or not)
My Tau have one unit vulnerable to lash that I don't want to be vulnerable--an unmounted
FW squad. However since it's so small (6 man) I could really care less if it gets lashed. I count on it being destroyed every game anyway, regardless of what I do, and if it sucks down a lash death so much the better. The rest of my army is
JSJ or stealth or vehicles, and is immune. If you run 72 fire warriors without putting them in devilfish, you better go first and hope you really hurt the Chaos army before they start lashing your fire warriors forward. I think most people have given up on that army, given it's many weaknesses, but if you haven't and run broadsides to provide anti-tank...well, you just got a better army but those
FW won't screen you for long and against Lash your cover units will get moved out of the way. When you run a mounted Tau army, you can still run Fish of Fury (although I don't personally think much of them) and zip forward to punish units using the lash to be more effective. Having lots of Pirahna's helps against lash in all Tau armies, because you can block all the sorcerors and even if a
DP can see you to lash you--most other units can't see you to shoot you. You usually only need a couple turns to seriously degrade a chaos army in it's capability, so while you can't ignore the lash in all configurations all you really need to do is reduce what the Chaos player can do with it.
Beating lash with Marines:
Since mech marines sucks, and chaos can kill you pretty easily...this means you have serious issues as a standard ground pounder marine army. Hood might save you from 1 lash per turn, but odds are you are going to get lashed. The only real way to defeat the lash is to slow it down. That means deploying on your table edge so the first turn no lash will be in range. Then you need to hurt the units that will hurt you when you get lashed. In essence, for most armies, you have a difficult time removing lash. However, if you cripple the units that were going to use lash to get to you--then you remove the threat of lash because frankly who cares if you get lashed when there's no stick to beat you with?
Tip: If you think of lash as moving you into range instead of your enemy moving into range, and just plan ahead it will still do damage but it won't be overwhelming like when you don't plan ahead. It might seem fairly obvious to some, but alot of players just don't get it.
You move in his shooting phase, and then he shoots you so you get no shots before you get shot up
I will put more info in later, terribly busy at work and all.