Ulalala is a very special nickname for a very special someone. It is mostly used as a code name to avoid using your crush’s real name. Despite that, an ulalala is not just a regular crush - they are absolutely amazing, and even though their appearance might not their best feature, their splendid personality makes it all up. In rare cases, the nickname ulalala could also be used to name a girlfriend or boyfriend.
Lizzy: How’s ulalala?
Stella: Oh, well, he’s more than a crush now!!! He is absolutely awesome :)