When knocking out the elemental. Short is with your taming tools (rockets,cannon) etc. Back up a bunch till it goes into rock form then shoot a arrow at it to wake it back up. Use the time in between disguising itself and waking up to organize yourself or your team for the next attack of cannons.
For some reason, after the latest update, X-rock elementals (haven't checked other variants) are no longer tameable. Whenever you knock them out, they don't eat and don't have a taming bar. Forcetame also doesn't affect them, so I believe it's a glitch
To tame these turret soakers I’d recommend getting four metal gates 5 pillars 3 ceilings and 3 walls. For the trap and the pillars are supposed to prevent the golems rocks from hitting the cannon. AIM FOR THE HEAD