I've been playing volibear since his release. Messing with build orders, builds and how to play him at all. This truely is the only way to play him, you go full tank, or you go tanky dps carry. As volibear I play tanky dps, but I included a tank guide as well.
Insane amounts of damage
Great sustain in team fights
Once you get use to it, great farming
Slow movement speed to start
CC shuts you down pretty hard
Ignite negates your passive
Called noob for playing an "op" champ ( he's really not though :/ )
Standard tank runes and masteries, nothing special or out of the ordinary here.
Runes/Masteries (tanky dps)
For masteries I use 24/5/1 the 1 in utility is for the enhanced recall, the 5 for some armor and magic resist and then the enhanced heal. For the offense tree I use the standard ad carry side picking up crit hit, armor pen, and life steal, also adding in havoc for a little extra damage, and then I use butcher for a little extra damage to minions seeing as +1 ap is pointless and the enhanced summoner spells aren't used in this build. Executioner is CRUCIAL for this build as it helps W scale hard since your W is your bread and butter.
Pretty standard, the double warmogs and atmas is to give you some dps even as a tank, I will note that before the nerf to W and warmogs that I did a 4 warmogs atma build, and had 8000 health and W did almost 2000 damage, but that was really just for the lol's. Obviously with any tank you have to figure out who's dishing out the most damage on the other team and try to counter them from that, ap carry means you need more magic resist and ad carry means you need armor. When you die click the death log and see what you took the most damage from and counter it with your items.
Items (tanky dps)
This is serious business! No for real though, be patient and you will absolutely slaughter the other team, they won't know what hit them. I pick up doran's to start laning (see laning phase for more detail).
Then I grab boots for movement speed, and pick up 2 more doran's. Most think that this is a waste of money, but with volibear it scale's so well, you get health and attack damage, both of which make your W just do more and more damage. From there I pick up merc tread's since you absolutely have to have + tenacity with volibear because cc will shut you down! Then i get warmog's and you can really just hold those doran's till you can pick up the rest of the items.
Sword of the divine is really good on volibear because you have to auto attack to get your W anyway, this gives you attack speed and +100 magic damage on your fourth basic, and when you activate sword of the divine you get even more armor penetration, and you just start doing insane amounts of damage.
Getting the black cleaver will only add to your attack speed, damage, and its passive means they have less armor which means you're hitting harder.
And since we are stacking attack speed, and W has an attack speed steroid built in, lets grab some life steal, picking up a blood thirster is only helpful in lifesteal and even more attack damage.
Now many people may question this last item on the list. And no you are not reading the guide wrong, it is the hextech gunblade. Why? because you get more attack damage, you get a little ability power which helps your ult dish out more, and it gives you life steal and spell vamp, and on top of that you can activate it and deal a free 300 damage and slow an enemy down, then use q to catch them.
Now depending on how the game is going, it is possible to get hextech first, but I prefer warmogs since I get 3 doran's blades to transition well into the meta and late game.
Now since we are describing situational gameplay, the basic needs for voli are warmogs and tenacity, so you can actually build him a couple of ways.
That being said the basic items for a tanky dps voli are listed above. Use your opinion on how the game is going, the sword of divine and hextech are used because its +60% speed and its active gives you a free armor pen, and hextech gives you life steal and spell vamp, both of which are great on voli since his ult is ap, and therefore the splash spell vamp will give you a lot back. But sword of divine can be subbed for last whisper and a phantom, however that means you have to also drop something else from the build, so use your opinion on how the game is going.
Skill Sequence (both builds)
For both tank and tanky dps you max W first, q is pretty useless after you level it once since it doesn't get any extra damage, and it's only used to initiate so you aren't really worried about its cool down either.
Summoner Spells (both builds)
Heal and flash. Heal helps so much because people tend to think once your passive is gone, you're done, well with heal you can just keep going and going. Flash is obvious, volibear has no run away technique, so flash or ghost can be used. I prefer flash because usually in a team fight if you get low, you can just flash to the back of your team, or flash over walls. Don't forget flash can also be used offensively, more so with volibear because you can flash in and then use q to chase someone down, they don't expect you to flash in and chase them down, they'll keep their distance because of your q anyway, but with flash you can get in range to use q and then e and then its gameover for them.
Farming and Laning (both builds)
USE YOUR MANA! I can not stress this enough for any character that requires mana, use your spells, don't be afraid that you have to b, if you aren't using mana then you should not be using a champ that requires mana! Volibear with his built in steroid can push quite easily. A lot of volibears I see really struggle to keep a good cs. So try to use that W all you can, use your e to get some extra damage and fear the minions, and really go for last hits, you'll find it quite easy with the tanky dps build to be really really good at creeping, you'll check your creep score and be like oh, I'm ahead of everyone, how did that happen? Keep using W, do not be afraid to use your mana as volibear, recalling is ok to do.
If you are doing full tank, and you have a carry laning as your partner, give him the last hits, they are the carry they need the gold a lot more than you, the more you help them farm the better off you'll be as a team later on.
On top of being able to farm really well, if you play patiently and smart, you can catch the opposing laner out of position, flash in use q to fling him behind you, and W when hes below half health and they pretty much are either dead, or will be low enough where they have to recall. With voli I tend to play right up in the opposing lanes face, but if you can't seem to do that, you can always play passively.
With laning, I usually go in and out of the river brush, not only to help keep site on the river ganks route, but sometimes it will catch the opposing laner off gaurd when you flash and q from river and catch them. But this also allows you to keep an eye out for jungling ganks, usually you'll be able to catch them before the opposing laner pushes up enough for the gank, and you'll be able to either kill 1 and then the other or if you are solo laning voli, you'll see the gank and you can back up.
When the other team has a jungler I love to spend money on wards. Not only do they help you keep map control, but they also allow you to see those incoming ganks, and if you get use to farming and using your mana as volibear you will have extra gold anyway.
And lastly don't be afraid to use your ultimate as voli to clean up creep. It has excellent splash, and is really helpful when you need to clean up a lanes creep.
Meta-game and Team battles (both builds)
After the laning phase the team battles begin and you start to fight along side your comrades. With volibear, it's always patience, with any team battle good positioning will win you the fight. As volibear you can choose to do a couple of things:
You can rush right in use your ult do tons of damage and then run away and allow your team to clean up.
You can choose to be sneaky and come in from the side to target down a squishy.
Or my favorite, you can flash in to a tank use your q, and he's in the middle of your team, so he dies pretty quick. But as volibear, you do tons of damage, and since you want to kill squishies first, you can use flash and then q into them.
Since your ult does splash you can target the squishy down, finish them with W and then turn around and pick up quads quite easily. Your ult and W are your main attacks, q and e are mostly for chasing down, but if you see someone jumping your squishy, use your q and e on them to allow your squishy to get away. As soon as you get sword of the divine don't be afraid to use it, it is really helpful when you get in a squishies face, the extra armor pen is SO good, and it only has a 40 second cooldown, and lasts for 8 seconds, by the time it's used up the team battle is usually decided.
Usually your key presses for a team fight are flash in, q, e, r, use sword of divine, and then w. You'll be amazed at how much damage output you have, and don't be afraid to use flash to get in, and heal if you need to, you have a passive that heals you as well, so you can really sit in the middle of team battles and dish out godlike amounts of damage.
Conclusion (also tl;dr)
Key points as volibear:
You are an initiate, but you also deal out insane amounts of damage.
Use your mana when you are farming/laning.
CC will shut you down, but don't let it frustrate you (if it is shutting you down, grab a quicksilver sash and use it).
The later the game gets the stronger you are.
Don't forget to use your items active's!
Don't let them get to your squishies, use your q to throw them away and e to slow them so they can't catch your squishy and so they can't run.
Ignite negates your passive BE AWARE!
You have no getting away ability, constantly be aware of your flash cooldown.
As a tanky dps, if you run in remember not to just auto attack but target low health champs and the enemy squishies.
As a full tank, you are basically meant to die, and if they get your squishy before you die, you are not doing your job.