This one time, whilst staying at his house during the holidays, Sirius confessed to James how he felt about Remus. He also confessed that he and Remus had engaged in somewhat romantic activities such as cuddling by the Black Lake and snogging in broom cupboards. Sirius told James that he was frustrated and didn't know how to stop from stressing about the situation. James told him to write his thoughts down, get them on paper, in front of him, and re-read it until he understood.
The next afternoon, James entered his room to find Sirius asleep at the desk, and before him, a sheet of paper with writing upon it. James was curious, and so he read what Sirius had written;
I know a boy who does everything right. He doesn't put a single toe over the line, and he's hardly ever in trouble. He listens in class, he takes notes, and he does all his set tasks. He studies often, and hard. His name is Remus Lupin, and when he writes his name, he writes it impeccably. His letters are curvy and the lines are smooth and well done, and he puts a cute little dot perfectly over the 'i'. Remus's uniform is pressed and neat. His clothes are always clean, and the patches are sewn on well. Remus does the sewing himself, and he does it by the book- just like everything else he does. He writes by the book, speaks by the book, performs magic by the book, smiles by the book, flicks his hair by the book, holds hands by the book, he cuddles by the book, and best of all; Remus Lupin kisses by the book.
Later that night, as James was lounging in the living room, drinking tea, Sirius entered. James smirked, and when Sirius raised an eyebrow at him he said, "I didn't know you'd read Romeo and Juliet."
Sirius went, naturally, beet red.