Meaning. 随便 suíbiàn – whatever; (do) as you please.

Why can Wen Ning use Suibian?

So basically, Mo Xuanyu will never reincarnate and the body remains in WWX's possession as long as he fulfilled all of the demands of the sacrifices which he did. Therefore when WWX's soul assimilated into MXY's body it basically became his and that is why he was able to draw out suibian.

How do you use Suibian?

But when you say someone is very suibian, the meaning is negative, is saying that someone doesn't care too much, has bad behavior, for example: Yesterday, Liz came to my home, entered my room with her outside shoes, and eat my snacks without asking my permission, she said she's tired then lied in my bed.