Drain-tanking

Overview
Drain-tanking refers to a Warlock's tactic. It is the process of using Drain Life on your target to keep you alive while damaging the target. In most cases, this is coupled with the heavy use of DoTs on them.

In the 2.0 patch, Drain Life was buffed twice, making this tactic even more appealing. Both its gain from spell damage equipment was drastically increased, and the respective talent (previously Improved Drain Life, afterwards Soul Siphon (warlock talent)) grants a lot more damage increase.

In PvE, this is a quite popular tactic among Affliction Warlocks, as it allows the player to fluidly kill mobs. In PvP, it received more attention past 2.0.

How-To
Generally, the main purpose is to stack all available DoTs on the target (Corruption and Bane of Agony, for Affliction Warlocks additionally Siphon Life (warlock talent) and Unstable Affliction). Then the target's life is simply drained. Normally this will keep the Warlock at full health, while relatively quickly killing the target.

It works great in combination with Life Tap. Before engaging battle, you can tap to get full mana. Then, your life will slowly increase, as the gain in most cases is higher than the damage received. This effectively allows the player to constantly and quickly kill mobs with little to no downtime.

In time-critical battles, Nightfall can help you a lot, as it procs fairly regularly, providing extra damage.

How to build for Drain-tanking
Many of the previously listed talents for this build have been removed from the game or changed into primary abilities.

Talent Requirements
 * 1) Improved Corruption (5) - extra instant cast DoT
 * 2) Improved Life Tap (2) - boost mana/health cycle
 * 3) Soul Siphon (warlock talent) (2) - boosts Life Drain for each dot on the critter
 * 4) Siphon Life (warlock talent) (1) - Passive health drain and extra debuff (+4% Life Drain)

Talent Recommendations (in order of preference)
 * 1) Demonic Sacrifice - Sacifice Succubus for 15% shadow damage (includes life drain)
 * 2) Demonic Aegis - Boosts Fel Armour
 * 3) Nightfall (warlock talent) - Instant cast DD (random)
 * 4) Shadowburn - Instant cast DD (this could be considered a waste of 11 points)
 * 5) Demonic Embrace - More sta
 * 1) Nightfall (warlock talent) - Instant cast DD (random)
 * 2) Shadowburn - Instant cast DD (this could be considered a waste of 11 points)
 * 3) Demonic Embrace - More sta
 * 1) Demonic Embrace - More sta

Drain Tanking example build DP/MF.