I’ll make Goyle do lines, it’ll kill him, he hates writing,” said Ron happily. He lowered his voice to Goyle’s low grunt and, screwing up his face in a look of pained concentration, mimed writing in midair. “I... must... not... look... like... a... baboon’s... backside.

Ooh, you look much tastier than Crabbe and Goyle, Harry" said Hermione, before catching sight of Ron's raised eyebrows, blushing slightly and saying "oh you know what I mean - Goyle's Potion looked like bogies.