Sirius when he's around you.

You and Sirius were in Hogsmeade together, the other Marauders were close behind them. For the first time in his life, Sirius was nervous. You made his nervous because he was so in love with you. He hadn't asked you out yet because he was so scared that you'd say no.

"I bet you five galleons that Sirius will be too nervous to ask out (y/n)." James muttered to Remus, who grinned.

"You're on, be prepared to lose five galleons." Remus chuckled.

Let's just say that James now owes Remus five galleons.