An abbreviation to sister
secret intelligence service
you forget about
put your hands over your ears and sing la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la la...
Rihanna does not have a sister, but in fact she has two younger brothers called Rorrey and Rajad.