Yeah, so. It's really not that hard to write this scene so that Puck doesn't act like a date rapist. This is my offering.
“I can’t do this,” she insisted suddenly, pushing at his chest, and although it nearly killed him, he pulled back, trying not to groan in frustration.
“You sure?” he asked, unable not to sound hopeful that she’d change her mind.
“You’re Finn’s best friend,” she sighed, looking up at him with darkened eyes.
He shrugged. “So I won’t tell him.”
“Puck…”
“Look, I like you or whatever, okay? And we’re having fun, aren’t we?”
“Yeah, but… I mean, I’m president of the celibacy club,” she moaned, letting her head fall back onto her pillows.
He barely contained his smirk. “Yeah, but everyone in that club has sex. Like, all the time.”
“Oh, so you’ve slept with everyone else in the celibacy club?” she asked, arching an eyebrow, and he grinned.
“Maybe,” he replied, and she rolled her eyes. “Nah, just San and Brittany,” he told her, but that didn’t really help his case.
“You should go,” she sighed.
“Okay. But only if you really want me to.”
“Dammit, Puck,” she muttered, and she grabbed the back of his neck and yanked him closer. “If you tell anyone about this, I will castrate you myself.”
“Cross my heart and hope to die, babe,” he breathed before leaning down to kiss her as he slid his hand up her leg.
“What about protection?” she asked suddenly, and he finished a condom out of his pocket.
“Always prepared,” he said proudly, and she shook her head, but he saw her smile.
“Tell me again,” she ordered, as he kissed her neck.
“You’re not fat,” he whispered sincerely, and she pulled him closer.