Chapter 3: Bang inducing three Flat What's from Ragna and Tsubaki in about a minute
Chapter 4: The conversation regarding Noel's cooking ability:
Tsubaki: "Um, when you say you cook…well, Noel says she cooks, but…"
Ragna: "It's terrible, huh?"
Tsubaki: "'Terrible' doesn't do it justice."
Ragna: "Totally inedible?"
Tsubaki: "...Try 'explosive'."
Ragna: "What the hell did Noel make that exploded?"
Chapter 6: Almost everything Platinum does, especially her reaction to Ragna and Tsubaki making out and this exchange:
Platinum: "Luna's sorry that Ragna's such a total careless dumbass that anyone could steal his sword."
Ragna: "And Ragna's sorry that he's about to rip Luna's face off. And wear it."
Chapter 9: Kokonoe interrupting their make-out session
Makoto interrupting Tsubaki's attempt to say “I love you” and the conversation that follows
"Just spit out that you love him already! Sheesh!"
At Fate's Hands
Chapter 1: Bang and Platinum meeting for the first time. And most of their interactions from there, really.
Chapter 2: The strategy conference, which gets derailed like no other and only stays on track due to the valiant efforts of Tager
Makoto: “And then fire consumes the Library and destroys its armies and purges the streets of its supporters and why are you looking at me like that, Noel?"
Chapter 5: Makoto deciding to see if Ragna and Tsubaki are clothed underneath their blanket...by pulling the blanket off.
Bang insisting on fighting Jin alone, right after lecturing Carl on the importance of allies
Hazama trolling the Duodecim.
Chapter 12: Gesshoku walking in to find Ragna and Tsubaki frenching each other....topless. He takes it remarkably well for a father, but it's the explanation as to how they're discovered which is the icing on the cake.
Tsubaki, deadpan: "You put the lock Ars on the wrong side of the door."
Chapter 19: This exchange:
v-13: "Assessing damage…negligible."
Taokaka: "Negligetables? You have decent taste, flappy-flap. Here, come and have lunch with Tao! You'll have to pay, though."
"…Status: confused. Requesting explanation."
"Mew? You don't know what lunch is, flappy-flap? You confuse Tao." Taokaka cocked her head, eternal smile faded into a concerned grimace. "Why, you're so thin, meow. And your boobies are so small, almost like lacking lady's…you don't eat much do you? Mew, don't worry, Tao will help you-"
"Intelligence: nonexistent. Threat level reduced to C."
"Ooh, Tao likes treats, too!"
"…Reinitializing termination protocol."
Chapter 23: Rachel and Valkenhayn hold a conference with Ragna, Taokaka and Nu. How it goes should be rather obvious.
Really, Bang and Platinum in general.
Bang: "...May I ask what happened to you, Miss Platinum?"
Tenshin: "When you attacked Tager, she insisted on slamming her face into a wall while chanting a mantra of 'idiot'. I was tempted to do the same.