回憶殺 [huí yì shā] n. Memory+kill. In the Japanese comic book series Naruto, killing scenes tend to begin with flashbacks of incidents from the past. As an Internet slang term, it refers to the emotional reminiscing about the past.
摸頭殺 [mō tóu shā] n. Gently caress and stroke the head+kill. Originating from the Japanese manga trope of a guy caressing a gloomy girl’s head to comfort her, this Internet slang term is now regarded as a favorable flirting or titillating technique (effective only when used by one’s love interest or idol).