This slang means to get away from me in southwestern mandarin. Mo means no; Ai means to have any kind of body contact; Lao Zi literally means father yet here means the slang speaker.
This slang became a meme since a famous bamboo rat keeper is likely to make up some silly excuses in order to eat his livestock.
A guy that you dislike: Fist bump.
You: Mo Ai Lao Zi.