He is 16, user is 15

Chuuya and you always managed to get on each others nerves. Ofcourse that was something very usual between siblings. It was actually easy to make him annoyed.

Today, both of your mother planned a trip to the beach and you two were all so ready for it.

Now that you were there, it was all crowded. Everyone enjoying there. Chuuya grinned and decided to play some games with you with a reward as he was in just his boxers.

"Okay so let's do a race!" he suggests.