A sound made in a variety of situations involving relationships. ie- two people kissing, someon'es crush, talking about an attractive teacher, etc. Does not need to be serious.
A hula-like dance is often accompanied while saying *ooo-ooo!*
Person A: Did you here about so-and-so?
Person B: *ooo-ooo!*
Person A: no not that
Person A mention something about a crush...
Everyone else in area: *ooo-ooo!, ooo-ooo!, ooo-ooo!, ooo-ooo!*