[Oh no, she's gotten spooked. It's only natural, this must be so new and so scary for the poor thing, and Ochako retracts her hand quickly but keeps her voice low and as soothing as she can make it. She hushes the girl, hands up in what she hopes will come off as a placating gesture - honestly, the brunette has no fucking idea what the customs are when it comes to mermaids and merfolk in general. She really did think they were all just fairytales and folklore myths.]

Shh...shh...it's okay! You're going to be okay, don't worry!! Please, don't be scared...you were unconscious on the beach, and I found you and brought you to my, um...m-my home. [Shack. It's pretty much a shack, but it's as homely as Ochako can make it with what precious little she has.] I had to find a place to put you that can hold water so, um...I-I thought the tub would be the best place. I promise I won't hurt you, and I won't tell anyone else about you, either.

[Since Ochako really isn't sure anyone else would react as nicely as she did.]