Can also be read/said as "Harr", "Harr harr", etc. You may also use all capitals, if trying to get the point across. It is indeed another form to laugh, which indeed makes everyone else giggle. Squares really only don't know what this esquisite word is. It is used by many people, and German teachers, around the globe.
Abigail: OMG my house reeks like salt
Maddie: HAR HARR HAR! abs, you're hilaious!