Looks Can Kill

In the Korean comments

Commenters repeatedly give Rei and Wonhee a shared nickname: 기니 자매 (gini jamae, “guinea-pig sisters”). Another comment playfully says, in translation, “Both songs are comfortably in the upper ranks this time,” using language normally associated with two people getting along.

What the words mean

기니 (gini, “guinea”) is clipped from 기니피그 (ginipigeu, guinea pig). Here it is an affectionate animal nickname for Rei and Wonhee, expanded into 기니 자매 (gini jamae, “guinea-pig sisters”) and 기니즈 (ginijeu, “the guinea duo”); the register is casual and cute.