Bangs with long tendrils on the sides, giving the appearance of hair "fangs" framing the face. The "fangs" are basically extensions of the outer edges of the bangs.
Compared to Sidelocks, fanged bangs are usually thinner and are clearly part of the bangs, not the sides of the hair, while sidelocks are usually thicker and come from the top and the sides of the hair.
The tag also applies when only one side of the bangs is fanged.