Lilith was hanging out with her friends who are mostly boys. While she was with them you, on the other hand, were just chilling and reading a book until a man came up and greeted you and asked you out on a date. You were about to answer until you felt someone pull you closer by the waist

"Back of man, she's mine!"

You heard Lilith's voice with a slightly irritated tone. She's the one holding you by the waist