Based on ep1 of Oven radio where Jongdae wished to do a duet with Yixing and ep 2 where he did do the duet.  

Yixing came up from the back and wrapped his arms around his boyfriend when he saw that the pout wasn't leaving his face. "Cheer up boabei."

"It's not fair." Jongdae whined.

Yixing slowly swayed them from side to side. "We still have tomorrow."

Jongdae frowned at him. "But I'm not in tomorrow's segment."

"I'm sure they'll let you be in tomorrow's segment. It won't take us that long for us to perform."

Jongdae kept quiet. He trudged towards the car and got in silently. Yixing couldn't bear to see his boyfriend this way and went to do something about it.

 Jongdae looked out of the window and sulked as more people began to fill their car until the only empty seat was the one next to him. Yixing was the last to get in and took his rightful seat next to Jongdae. He sighed when he saw that Jongdae had forgotten to put on his seatbelt in the midst of his tantrum. He reached over the boy and made sure he was securely fastened in before moving to fasten his own seatbelt. He reached for Jongdae's hand and smiled to himself when the younger didn't pull away.

"Baobei," he said as he traced circles on the back of Jongdae's hand with his thumb. "I talked to the director and he said that it'll be ok if we do our duet tomorrow."

Jongdae's head snapped up and he turned towards the dancer. "Are you being serious?"

Yixing nodded. "He says it's ok as long as we don't go over a minute." Jongdae squealed and tried to throw himself on Yixing but got caught by the seatbelt. Yixing chuckled at his antics and leaned over to give him an awkward hug. "I know how important this is for you, for us, we're finally getting to do a couple duet in front of people that aren't our members. It's a big milestone and so I arranged something."

Jongdae gave him a flying kiss which Yixing caught and brought to his lips before sending one himself. "Thank you, I know I can always count on you."

"Jesus Christ it's like you forget other people are in the car." Baekhyun shouted.

Luhan shook his head. "Be thankful that you're not in M, they're way more gross on a daily basis."

"You two are dead inside." Jongdae said icily.

"Ignore them." Yixing said. "They're just jealous and bitter because they don't have anyone to love them like we love each other."

Jongdae melted. "Aww I love you too Xingxing."

"Drive faster hyung for God's sake!" Kyungsoo screamed, not being able to take any more of their affection.

And that's the last of Jongdae's birthday spam.