It basically means to chill out, and not make a big deal about something.
Like "don't have a cow" only cooler.
Ex:
Amanda: "I am sick of always being the one to clean up around here! You'd better start cleaning up after yourself or I'm going to sleep with your brother again."
Jason: "Fineee damn, don't bust a herpe over it."
Jason: "And leave my brother out of this!"
Alyas is the sweetest friend you'll ever meet. He is kind, loving, annoying and a bitch at the same time but you bare with it because he is worth it. If you think you don't need anybody else in your life you are wrong because there is always Alyas!
Alyas is the best person you'll ever meet! So don't let go!