lmao       
very informal (also LMAO)
 笑死我了(网络或短信息用语,laughing my ass off的缩写)
abbreviation for laughing my ass off: used, for example on social media and in text messages, when you think something is funny or you intend it as a joke
  I look even worse than you do lmao.
 LMAO at all the comments.
 I was LMAO reading about that poor man's fingers.
 - More examples
 - I was so thirsty I could have sucked moisture out of an old sock, lmao.
 - LMAO reading all of this feedback.
 - His music is awful and his acting is worse. Now he wants to be a film director? lmao!