In addition to the Wickerman Festival quests, players are able to get a strong buff from the Wickerman - Invocation of the Wickerman, which increases your Health Regen, Mana Regen and Stamina by 25% for two hours. To obtain this buff, you will need to interact with the Wickerman Festival NPCs in Tirisfal Glades, near the border to Silverpine Forest,
Horde players are able to grab this buff by going to the Wickerman at any time between 8 pm and 6 am server time, and simply loot the Wickerman Ember that will be on the ground around the Wickerman statue. If you're actually by the Wickerman statue at 8 pm, you can see Sylvanas Windrunner burn it!
Alliance players can obtain this buff with a far more difficult task - They will need to pull one of the Wickerman Guardians guarding the Wickerman statue and kill them. They hit very hard and have around 10k hp, so bring friends! Once the guardian dies, they will let out Wickerman Guardian Embers on the floor, which can be looted to obtain the buff.
Wickerman Statue/Guardians Location