Alter Aeon Online Help

Keywords are:  'necromancer skill lifetap tap'

Skill: life tap                 Lvl 21 Necr  (28%)
                                (critical)   Requires: blood sacrifice
                                Group: Necromancer Blood Skills

Usage:
lifetap <hp amount>
lifetap stop

This skill allows a necromancer to tap their own life in exchange for
mana.  Blood is required for this, and the necromancer must let his
own blood for the exchange.  This process takes time, but can be
stopped at any time by using the 'lifetap stop' command.

This skill cannot be used in combat.
You cannot kill yourself with this skill.
At higher skill levels, it becomes possible to safely let blood faster.