Sarah was fully prepared to lose the fight when Peter could no longer overcome his clear training, but she didn't mind at all. However, when he set himself up to essentially disarm her, she realized he'd taken Monty's disgust as an idea, or a challenge. That turned 'not minding' into a very willing loss as she did indeed melt against his arm, smile forming even as she kissed him back.
"Best rewrite ever," she muttered against his lips before pulling back slightly, also cognizant of having an audience.
Monty was still too busy scrunching his face up into truly distorted expressions of disgust to do more than continue to voice a long, seemingly tortured 'eww', but Simon was game for answering Angela.
"It's gross, Grandma," he said, hitting the ground with the lightsaber as he rolled his eyes. "Kissing? I wanna be on the Dark Side now."
"I don't think it's gross at all," Sarah said, wrapping her other arm around Peter's neck as she nuzzled the side of his face, eyes still on the boys and bright with unholy mirth.
"Saaaaaarah!" She hadn't realized her name could be voiced quite like that, the obvious dismay in stereo. This was all too much fun.
"What? Oh." Her expression turned serious as she nodded her head, as if just realizing something Very Important. Behind the facade, she was only barely keeping back laughter. "I know what this is. You guys want kisses too, don't you?"
The resulting shrieks of horror and disgust left her clutching Peter as she giggled helplessly.