Kekkaishi is a series about humans with the power to create mystic barriers to stop and destroy demons that infest their school.
Tokine Yukimura is shown bathing in at least three chapters:
After "Toki" (Tokine Yukimura) freaks out over a bug, she trips and throws her stew at "Yoshi" (Yoshimori Sumimura). He is so concerned with catching her that he is unable to avoid it and it falls all over his head. Some of it also hits his little brother "Toshi" (Toshimori Sumimura) and his two schoolfriends, "Gatcho" (Gaku Mikawajima) and "Konta" (Taichi Komagome) so the three takes a combination Shower and Furo and Furo Tub session. Yoshimori is not shown bathing with them, but when the scene cuts to them cleaning up the mess, he is shirtless, with a towel around his neck, and there isn't any curry on his head, which implies that he took an Offscreen shower before them, which makes sense since he would be the dirtiest.
Atora Hanashima is a monster trainer that visits her ward Gen while Yoshimori is visiting him and eating cake. At 5m45s she hugs his face to her amble chest, blushing happily after learning Gen had finally made a new friend. After he exclaims, embarrassed to be let go, she questions his embarassment, saying that they used to take baths together.
She makes another reference to this later in the episode, at 22m15s, when she suggests they bathe again. Yoshimori and the dog pet of Tokine tease him about it.
When Gen visits Yoshimori's family home, Yoshi's dad suggests he take a bath. When he refuses (wanting to leave) Yoshi teases gen about only wanting to take baths with Atora. Yoshi then burns his arm testing the temperature of the bath water. Gen Shishio is revealed as having taken an Off Screen Bathing session as Yoshimori questions if he washed the shampoo out of his hair in a later talk, indicating that he did give in to Yoshi's dad's request.
This time, at 20m15s, Atora asks Yoshimori if he wants to bathe with her, while visiting the apartment he's staying at.