Just erotic. Nothing kinky. It's the difference between using a feather and using a chicken.

The line uses Pratchett’s characteristic comic literalism to draw a boundary between the merely suggestive (“erotic”) and the overtly transgressive (“kinky”). By contrasting a feather (light, teasing, controlled) with a whole chicken (absurdly excessive, messy, and unmistakably physical), the speaker implies that intent and degree matter as much as category: the same general idea can be playful or can tip into something far more extreme. The joke also satirizes how people try to sanitize or rebrand sexual content with careful labels, only for the metaphor to reveal how arbitrary—and how funny—those distinctions can be when pushed to their logical conclusion.