Japanese onomatopoeia for a bell ringing, with two tones. The original noise was borrowed from
game shows where whenever a
correct answer was given, the tones would ring out.
It is now also included in
casual conversations where there is one person trying
to teach and be
cute at the same time. It helps lighten the
mood.
For an idea of what it sounds like in actual speech, try imitating the prototypical
doorbell noise, "
ding dong!"