Ymir is free for now because Christa is not around so she decides to look around for an interesting person and accidentally saw Annie and decides to tease her, who is free for now and is reading a boring book quietly. It's a story about them chatting friendly while not being honest, waiting, teasing, and being friendly with each other.

Yo!

Reading that book...again?

What a boring person-

tch

...Thanks

I just wanted to drink and prepared one for you

Thanks. I thought you would only do that for Christa

You should know. I don't want you to catch a cold and spread it to Christa

Sorry for interrupting. The coffee was delicious.

Thanks for the drink (kiss)

You should know your limits! Hey, stop there!

DWAHAHAHAHAHAHA