Internet High Five, used when online and you want to give the accomplished other a high five, but you are unable. So to convey the idea that a high five would be given in real life, you say IHF instead.
person one: hey, i just one first place at the food eating contest!
person two: Wooo! Awesome! IHF!
7👍 17👎
an acronym for "i hate furries"
Son: Dad, I'm a furry.
Dad: ihf. I got to Heb and get milk.