Whats the best way to kill yourself?

You know what's the dumbest trend nowadays with high school kids......the "Kill yourself" statement that they use as a "joke". I'm not sure if it's a thing everywhere but I guess it is at my little sisters high school. One day she came back from school and she told my younger brother to kill himself after he dropped water on the floor. Of course when i heard this I had no idea it was just a trend going on in school so I talked to her and said some things to straighten her out.