Merman in My Tub S01 E09 My Naked Circumstances

Wakasa is shocked when Tatsumi leans over the tub and announces it stinks. Tatsumi cleans the tub responsible for the odor and transfers Wakasa to a children's pool. Saying, "Brother, tell me if you're using the pool," Kasumi mistakes Wakasa for Tatsumi and hugs him.