Shortly after the birth of her first child, a letter-writer who calls herself “Tantrum Daughter” lost her mother to suicide. Now, with a second child on the way, Tantrum Daughter is overcome with pain and anger. After reading Morgan Jerkins’s essay “How I Overcame My Anger as a Black Writer Online,” the Sugars enlist her help to answer Tantrum Daughter’s letter. Ms. Jerkins frequently taps her own anger in her essays on police brutality. The Sugars and Ms. Jerkins discuss the connection between trauma and rage, and …