you up

you up

slang A text sent to ask if someone is awake, typically as a pretense for a casual sexual encounter, especially late at night. The letter "u" is commonly used instead of the full word "you." Hey u up? He just sent me a "you up" text—should I let him come over?
See also: up
Farlex Dictionary of Idioms.
See also:
  • the watches of the night
  • be shacked up with (someone)
  • fuckbuddy
  • night owl
  • a night owl
  • pull an all-nighter
  • wait up
  • up with the lark(s)