Cool Your Head! (およしなさい, O yoshi nasai) is Ikaruga and Katsuragi's Secret Fusion Ninja Art in Senran Kagura 2: Deep Crimson. It requires at least 3 ninja art scrolls from both of them to use. Like all Secret Fusion Ninja Arts, its power increases with the characters' mutual Affection.
Ikaruga preps both her and Katsuragi to prepare for their attack but is cut off from an unsightly incident. Katsuragi moves behind her and grabs hold of her breasts, groping them without shame. Ikaruga, now enraged, slings Katsuragi over her back and proceeds to smack her with Hien, sending poor Katsuragi barreling right into the enemies.