Yes, usually, FS is safe and should be used with children. It is not full of harmful, offensive, or inappropriate meaning. It only serves to make kids chat fast and informally with their peers. Nonetheless, like any other slang on the Internet, parents are better to be alert of the bigger discussion children are involved in and provide them with secure virtual environments. The term is not a bad word however keeping oversee of the overall behavior is never a bad practice. Know more about what does fs mean in text