[As the grip on his arms tightens, the more he's becoming aware that this might end up in a cat fight. Far be it from him to discourage a fight, but this isn't going to be the kind of fight he likes to revel in, but rather a passive-aggressive verbal slap fight that he'd rather not get started. If you're going to fight ladies, use your fists!

He's glad that the mermaid doesn't seem to be taking Yoimiya's bait, but on the other hand the more she talks, the more it seems like she's just trying to get his girlfriend's goat. He knows that it's not hard to manipulate her, being guilty of that himself from time to time, even if it's all in good fun for the two of them! But this is getting dangerous, and he wonders how this'll all play out. He'll put an end to this if it gets out of hand, but...

It might end in a fist fight after all.]

We've been training together for some time now, [he adds onto Yoimiya's statement, ignoring how the mermaid blatantly hits on him,] and I've actually taught her how to use a sword recently. She's gotten pretty good at it.

[He says proudly, the statement both him bragging about Yoimiya's ability and a warning that she just might cut her if she keeps hitting on him, but it doesn't stop her. She bats her eyelids at Childe once, making sure Yoimiya can see it plainly.

That sounds fun. I've never fought with a sword, but I've always wanted to learn.]