AN: Written for the Ten Pairings challenge!

Regulus/Lily

Club Imperio:

Mojito: Set your story during the summer holidays. (Word) Mouthwash.

Frustration (Regulus/Lily)

Regulus stumbled his way down the stairs of the House of Black. He was still half asleep but Kreacher insisted he should wake up, stating that he had let him sleep in for too long already. It was the summer holidays and his parents had left for Switzerland. They were meeting another dignitary that Regulus hadn't bothered to remember the name of.

Him and Sirius had had the house to themselves for the four days their parents had been gone. However, they were returning today—that meant Sirius was likely to be around a lot less. It was a shame.

Regulus focused on the taste of the mint mouthwash on his tongue, trying to distract himself from the painful lump in his throat. Sirius had been speaking to him properly for the first time in a long time… Regulus wasn't sure if he was ready to give that up just yet. But he knew, regardless of whether he was ready or not, that Sirius would withdraw from his life once again, when his parents returned. He didn't understand why Sirius couldn't just put up with them. He had done exactly that for the first eleven years of his life. All he had to do was get through school and then he would be fine to go his own way—away from their parents if that was what he wished.

Entering the living room, Regulus found Sirius sprawled across the sofa, reading a magazine.

Sirius looked up from his reading material. "Hey, little brother."

Regulus rolled his eyes. Of course Sirius would greet him like that. "Hey… big brother. You look a little out of place," said Regulus, gesturing to the ancient material of the sofa. Sirius was wearing a leather jacket despite being indoors and was reading a magazine about Muggle bikes. Motorcycles.

Sirius snorted. "I feel out of place," he said. "That's why I'm going to visit James to give him advice about Lil—about a girl." Sirius tried his best to cover his slip up but Regulus already knew that James Potter had taken a liking to Lily Evans. Regulus was surprised that Sirius seemed to care more about keeping it a secret than realising he was leaving Regulus alone on the last day they had together.

"I already know he likes Lily," Regulus said, closing his eyes and taking a deep breath to steady himself. I wouldn't do for him to get angry. But a vivid red flashed on the backs of his eyelids when he closed his eyes and when he exhaled it reminded him of her soft sigh as he walked past her.

"You do?" asked Sirius, looking completely confused.

"I just said I did." He just about stopped himself from rolling his eyes at his brother. She rolled her eyes a lot—especially at Potter's antics.

"Thank goodness for that," said Sirius with a relieved sigh. "Any advice?"

"Advice on wh—" Regulus cut himself off as he realised what his brother was asking. He couldn't be serious; he was asking for his advice on how to get Lily and James together? Actually, he could considering he didn't know that Regulus liked Lily. "I have no advice, sorry," he said with a shrug. He was lying. But why on earth did his brother think that he wanted to help the brother—and now potential girlfriend—stealing git?

Sirius groaned. "I have no idea either… Well I'd better be off. I don't want to be late. See you in a bit, Reggie." And with a wave, Sirius walked out of the room, leaving a seething Regulus behind. It was only when he heard the front door slam that he allowed his mental barrier to disintegrate, letting the tears of frustration flow down his face.