Hbh stands for HeartBreak Hotel, which comes from a song. It usually refers to a person being rejected by his/her crush. It was invented by a girl who likes to use acronyms for almost any words.
Basically HBH stands for heartbreak hotel. It was derived from a song and is commonly used when heartbreak happens. When that does happen all you gotta do is check-in to the heartbreak hotel.
Me: yo guys im so depresed
Dave: wsup g
Me: Time to check in hbh