Cases in which an individual enjoys drinking his or her own blood, such as by deliberately wounding him/herself at the base of the tongue in order to suck at these wounds and swallow the blood.

This can be one of the symptoms of Renfield's Syndrome, (named after Stoker's character) AKA clinical vampirism.

the thing that you don’t have when you’re phones percentage is over 20

Autovampirism is the act of one being attracted to tasting or licking their own blood. Particularly could bite the tip of their tongue and take up the blood or take the blood of a partner during intimacy.