With its short cast time and remarkably quick recharge, this skill can be used repeatedly to spike for very high damage over time. Unlike its sister skill Vile Touch, Vampiric Bite consists of life stealing rather than damage, so staying alive while spamming this skill at point-blank range is not much of an issue. However, at 15 energy, the cost of using this skill can be prohibitive without some form of energy management.
One effective strategy occasionally seen is to have four to five Blood Necromancers working in tandem, casting Blood is Power and/or Blood Ritual on one another to counteract the high energy cost of this skill, then all focusing their Vampiric Bites on a single target, healing themselves for a tremendous amount while doing a downright frightening amount of armor-ignoring "damage" over a short period of time. If properly set up, this can be repeated very quickly on different targets.