like if I can't help falling in love with you? #Hearts2Hearts

In the Korean comments

One comment describes the performance as “Carmen’s piano and Dahyun’s lullaby,” saying that combination might send the commenter to sleep. Another simply asks, in translation, “Is Tella asleep?”

What the words mean

카스텔라 (Kaseutella) normally reads as “castella,” the sponge cake, but here it combines Carmen and Stella into a single affectionate nickname for the pair. That is why comments such as “카스텔라 (Kaseutella) is so soft” are talking about the performers, not food.