vampire time

noun3

1. •
   (informal) Night; the time when there is no sunlight.

   • In the night, in the smoky smoky night: vampire time. Rebop syncopate do the dirty bop, request "Sixty-Minute Man," hear the Shammies, sing the song. — 1981
2. •
   (informal) A schedule in which a person sleeps during the day and spends much of the night awake.

   • Undergraduates say they live on vampire time, sleeping in class, active after dark. — 1997
3. •
   (slang, euphemistic) A woman's menstrual period.

   • But what would he have thought about the female character in a novel I recently read who, noting that she was in her menstual period, called it 'vampire time'? — 1985