S1·E5 Became No Good?

Nozomu's brother puts a bracelet on Kouta's wrist that inflicts high amounts of pain if he becomes sexually aroused and Chizuru worries that if she tries her normal flirting behavior she could eventually kill him. Chizuru holds back her feelings for a couple of days but with intense self-restraint (to the point she starts having withdrawal symptoms). Meanwhile Chizuru's brother and Omi Kiriyama, a sickle weasel, try to negotiate with Nozomu's brother to take off the bracelet with violence but all goes wrong when they discover that he is really powerful; Chizuru later joins the fight but is defeated. Nozomu hears her brother's victory howl and tells Kouta that Chizuru is in danger; at the scene of the fight, Kouta and Chizuru combine to make quick work of Nozomu's brother.