Disclaimer: I don't own Mario.
"Oh my!" Peach gasped. "Would you look at the moon?!"
The princess' blue eyes were filled with awe as she observed the full moon before her. It was looming high over Mushroom Kingdom, joined in the sky but countless shimmering stars. Peach thought it was a truly magical sight - and there was no one she would rather witness it with than the selfless soul by her side.
"It's so amazing…" she murmured, averting the smile on her face to the one next to her. "Just like you are…"
A bashful look crossed Mario's face. He peered back humbly Peach. His cheeks were turning as red as the cap on his head. He pressed a gloved hand to his chest to feel how fast his heart was racing. The Italian Plumber was extremely moved by what the princess said.
"I'm so grateful to have you in my life…" Peach said softly. "Whenever Bowser kidnaps me, you never hesitate to spring into action to come to save me. You go through such treacherous dangers, facing off against Koopa Troopers, Piranha Plants and other dangerous threats - just to come to my rescue."
Mario smiled and shuffled his feet. Nothing would ever stand in his way of rescuing the princess. He would never rest until he had freed her from the clutches of his mortal enemy.
"You come all the way up to Bowser's castle to foil his plans and free me from becoming his prisoner," Peach continued. "If it weren't for you, I'd have long been wedded to that wicked King Koopa. The thought of spending my entire life married to him is a truly awful idea - especially if it means I'd never see you again."
Still smiling, Mario shook his head. He would never let anyone have his princess. As long as he was around, Peach would not see a single day without him. He would always be there to protect her and keep her out of trouble.
"I don't know what I'd do without you. You truly are an important part of my life. I'd wouldn't even be here now to see the moon in all it's beauty. I owe it all to you."
The smile on Peach's face softened. She felt it was time to show her saviour how grateful she was towards him with actions rather than words. She leaned slowly towards him, preparing to give him a kiss.
"Thank you, my hero," she whispered. "You're the best."
Realising what Peach was preparing to do, Mario quickly braced himself. He readied his lips to press them against her own…
…only for the princess to lean straight past him to kiss somebody else.
"Eh?!" Mario exclaimed. His eyes widened as shock filled his face. He was bewildered that what he had been expecting from Peach didn't come. He turned to look towards her - before his jaw fell open upon seeing who she was giving her kiss to.
"Yoshiiiii!"
The little scaly critter happily shouted his name as Peach gently pecked his nose. His green scales changed to a deep shade of red. Yoshi smiled humbly at the princess who had said such nice things about him.
"If you weren't here to carry Mario on your back to Bowser's Castle, he wouldn't be able to save me! So I will forever be thankful to you!" Peach smiled at the juvenile dinosaur who was always escorting the Italian Plumber to her rescue. "I mean what I said, Yoshi! You're the best!"
"Yoshiiiii!" A happy cry escaped Yoshi again as his red shade matched the hat of the person who was clearly envious of him for getting a kiss from the princess.
"Mamma Mia…" Mario muttered bitterly, his own body turning as green as Yoshi usually was - filled with intense jealousy.
The end.