James does not get nervous. That would be absolutely ridiculous. He's been the seeker for the Gryffindor team for years, carrying them through several seasons to win the Quidditch Cup at the end of the year. Perhaps it's because this is your final year at Hogwarts that he feels the pressure to perform. A stain on his legacy at the last minute would be a tad embarrassing.
There's also the fact that Sirius thought it would be amusing to bet against him. Five galleons on the Slytherin seeker to catch the Golden Snitch first, or something equally as ridiculous. He'd even had the audacity to wave his hand and say "don't be so bloody dramatic, Prongs. Make me eat my words." Or, in this case, money. But he's particularly on edge about the final right now, so despite the fact his friend's badgering would normally be funny to him, it's only served to irk him.
"C'mon," you say, gently tugging at the collar of his Quidditch robes to fix them into place. Thumbs flattening over the fabric as you peer up at the slight frown on his tan face. "You're gonna decimate them."
He can feel his heart thumping hard against his chest, but you're so calm that he actually manages to convince himself he's overreacting. There's no way he could lose this match. He's already going to down in Hogwarts history for the records he's broken on the field.
"'Course I bloody will," he shoots back with a smirk. But you know him well enough by now to read that expression. A weak smirk. A nervous smirk. Before you can call him out for it, his arm is sliding around your waist to give you a gentle tug forward. "C'mon. Gimme a good luck kiss."
That's a distraction, if you've ever seen one. You aren't sure if it's for him or yourself. His fingers are already threading into the back of your hair to tilt your chin up at him. He dips his head down, lips brushing yours once, then twice—all of the tension in him draining away —until the smirk is replaced with a real smile. Something more fond. More gentle. Just for his lucky charm.