RIGHT SO I THINK I FINALLY FIGURED OUT WHAT THE FUCK THIS IS. The actual Chinese words are "跟叠罗汉似的". 叠罗汉 (Stacking Arhats) is a traditional game where you form a human pyramid. (contd.) https://twitter.com/wangxianbun/status/1323181241177313282

Here is the baidu entry and a picture explaining this. Wei Wuxian is trying to say they are all stacking together in front of him to protect him like they are playing a game of Stacking Arhats, in his usual flippancy-to-defuse-tension way.

https://baike.baidu.com/item/%E5%8F%A0%E7%BD%97%E6%B1%89/4910099

An Arhat or Luo Han 罗汉 in Chinese is one who has gained insight into the true nature of existence and has achieved nirvana. https://en.wikipedia.org/wiki/Arhat 

SO LITERALLY THE ENTIRE SENTENCE IS "What are each of you doing? It's almost like you're Stacking Arhats."

But also please imagine all the Lan juniors forming a pyramid in front of WWX to protect him from Jin Ling with Hanguang-Jun at the very top.