Stands for 'Keep the Backstreet Pride Alive' used by Backstreet fans all over the world to show their love and support to the band (Backstreet Boys). The boys themselves know and use the term.
Also used: 'Keeping the Backstreet Pride Alive'
Adriana: Hey! do you like the Backstreet Boys?
Paola: Of course!! I'm a Backstreet Fan!
Adriana: Great! KTBSPA!!!