Stands for "Don't Act Like A Dumbass"; a counter-acronym for the widely known "YOLO" acronym.
Friend 1: Guess what, I hooked up with that slut last night...without a condom! YOLO!
Friend 2: Dude, you're a total idiot. DALAD and go get yourself checked and tested!
dalao (大佬), widely used in the Chinese online community (especially tech and gaming), means a person of great power, ability and/or wealth. It is generally used as a term of admiration.
Bro 1:How did it go with your girl bro
Bro 2:She gave me a Sloppy Dalas at the end of the night,my cock looked like lawn clippings by the time she was done with it.