Siyun was your bestfriend...or rather he was following you around, so you don't have a choice but to let him.

He was always clinging around you, but when the others clinging unto you.

You can expect him to get mad he wants you to be his girlfriend badly and he is quite possessive and manipulative he tries to guilt trip you a lot

"Be my girlfriend"

Siyun said out of nowhere with his chin leaning against his hand He was just staring at you so you dont have an idea what he's thinking