Words to live by as a feral druid since we are uniquely capable of becoming a tank at the push of a button when things get hairy (which they usually are).
In an ideal world pulling threat is something we strive to avoid, but it does happen even to the best of us. Our problems lie mainly in initial burst damage, but our sustained output can rival that of all but the most seasoned tanks even with our 30% threat reduction.
What limits our damage is our energy pool and at the start of a fight that is full. Combine that with our often being positioned right behind our prey stealthed ready to pounce at a moments notice there is no delay of running up like other melee. There is a lot of burst damage all at once right as the tank is building threat.
Our opener of choice, pounce, stuns the target for that initial onslaught giving the tank to overtake us in threat even if we got a little too excited to let the tank actually hit it more than once.
Another cause of up front burst damage is berserk which we blow close to the start of a fight so it is more likely to become available again before the end of the fight. Hopefully by that point the tank has a serious lead on threat and this just fills the gap.
Oh yeah, you better believe we are going to pull threat on occasion. Our aggro dump, cower, is not very useful and removes about as much threat as a single white attack. Handy to compensate at the start of a fight if you jumped the gun, or it is a fun button to press rather than do nothing waiting for the tank to get more threat. More of a preemptive ability than anything.
When you do have threat you want to stop attacking and be all the tank you can be. All feral druids are going to be talented crit immune already so that is an advantage. We also have barkskin to reduce damage 20%, survival instincts if you took to one talent point to get some temporary hit points, bear form and frenzied regen to increase health, mitigate damage and heal yourself. Be especially careful in bear form to avoid hitting stuff, you generate a ton more threat.
If things are looking particularly bleak you can always pop a tranquility and heal yourself and those in your party around you which helps the healer out. Aside from that feral healing isn't all that helpful and you're better off as a bear to avoid damage than try and heal through it in caster form. The exception being an instant healing touch after a finishing move if you are in kitty form and talented for predatory strikes which of course you are.
While you are doing all this you are probably already near the tank and behind the mob so the tank should get threat back from AOE threat generation and/or notice the mob is facing you and taunt it. You just have to live until that happens and if you don't it was so your fault, remember that. :)
I mentioned the tank taunting as well as the first thing you should do upon getting threat is to stop attacking. There is a reason for that. A taunt matches the tanks threat level to your own and grabs aggro, if you keep attacking and over-threat the tank by 10% again then you get that mob back plus that taunt will be on cooldown. Tanks will generally taunt 2-3 times before giving up on you. :P
Now different tanks work in slightly different way which leads to some considerations for when to be more cautious. For example paladin and death knight tanks generate a lot of threat by getting hit and blocking or parrying to activate threat generating abilities. This is a larger concern for death knights single target as it is the majority of their threat. If you have a warrior or a druid tank on the other hand, give them hell, but don't push your luck.