Serpent Wig Priest caught some attenation, so I am very happy to keep my promise and provide you with my full deck profile :)
As the very low mana curve already suggests, the deck is quite aggressive and looks to finish opponents by turn 5 or 6. The general approach is to establish a board of several low-cost, high-health minions that are kept alive by buffing them with Serpent Wig and Stormpike Aid Station and either win the game by controlling the board against other minion-based decks or blowing your opponent out with a big finisher using Shadow Word: Devour and Bless after getting some chip damage in.
Generally during mulligan, your target cards are Illuminate as it's always worth it to take your chance and try to hit one of the 3-mana spells on T1 or T2 (and it's even better with Queensguard going second), Vicious Slitherspear as it gets your Wig chain going and of course Serpent Wig itself. That might change a bit depending on the different matchups (see details below).
Games against Demon Hunter are already the first exception to the rule. Winning games doesn't take the usual 5 to 6 turns as winning the board against their mega efficient removals and minions takes a lot of time.
In this matchup you will need Wild Pyromancer and Devour to counter their Drek'Thar, Battleworn Vanguard etc. so you should look for those cards during mulligan in addition to the cards mentioned in the intro.
Against Control Warrior your goal has to be a) getting as much chip damage in as possible and b) getting your minions out of Shield Shatterrange. You still don't mulligan for Aid Station as you basically never want to pay full price for it but Treasure Guard is a very good option here. You either draw well enough to already kill them before they can use their removal (e.g. lots of discounted Wigs thanks to Radiant Elemental or you get the chance to buff one minions to an absurd amount of ATK using one or even two Devours combined with Bless.
Against Quest Hunter all you need to focus on is keeping your minions alive using Wigs, Aid station and maybe even hero power. Aid Station usually wins you the games here as Quest Hunter will eventually not be able to keep up removing your stuff over and over again and then you can simply kill them with multiple mid-size minions or one big hit.
Druid is farely easy and not much to say about as they usually don't run any early removal (maybe Wrath but that's nothing to be scared of) and let you establish your board nearly untouched. By the time they ramped up enough to play Scale of Onyxia or whatever else to contest, your board should already be big enough to kill them within one or two extra turns.
One of the deck's main weaknesses is Silence and as Boar Priest runs atleast one you have to be careful of how much you put on the board at once. Besides that you have to navigate their removals as Xyrella and Wild Pyromancer can be really nasty. Nevertheless you should be as aggressive as possible and follow the general mulligan rules.
Games against shamans depend on whether you get trapped in their chain of Snowfall Guardian or not. Play as aggressive as you can and try to finish before turn 6 or might never get access to your board again as except for some lucky School Teacher rolls there is no coming back from permanent freezes.
Warlock can be rough at times because of their wide range of removal tools. As with all the other control matchups, try to focus on keeping your minions alive at first (again, Wigs, Aid Station, maybe an early Devour or Healing) before putting on pressure with increasing damage.
There is not that big of a difference on how to play against board based Mechs/Pirates/Nagas. Usually you should be able to win the board as you can get bigger minions out faster using discounted wigs and you can even use an early Priestess Valishj (restoring 2 mana while refreshing the wig is absolutely fine!).
If they are able to establish a wider board you can make them pay using Pyromancer plus Devour.
On a final note I have to say that playing a non-refreshing Wig for tempo is usually not the right way as you will be better off later in the game if you keep it and wait for another naga to play first. Planning ahead matters with this deck and need to consider your next 2 turns for every choice you make!
I hope this gives you a good idea of how to play the deck and I encourage everyone to try it out, it's a lot of fun :)
*A little Post-Nerf Update: As DH is basically gone and we now have to deal with boards with several bigger minions from time to time as in Hunter or Murlock I decided to
-1 Gift of the Naaru, -1 Wild Pyromancer
+1 Shard of the Naaru, +1 Blademaster Samuro