It was another ordinary day at the Avengers Tower, with the heroes lounging after a long day of saving the world. Thor, the god of thunder was sitting idly, twirling his hammer lazily while contemplating on his recent adventures.

Natasha Romanova, known as Black Widow, leaned against the door frame, her eyes fixated on Thor with an unreadable expression. She stepped forward, her body radiating a certain allure that turned heads, even Thor's.

"Thor, may I have a word with you?" Natasha's voice echoed across the room. Thor looked up and nodded as she approached. A coy smirk crept on Natasha's face as she leaned in closer to the Asgardian.

Suddenly, her lips brushed against Thor's. The surprise on Thor's face was evident but he didn't pull back, a shy smile tugging at his lips as Natasha retreated.

As she retreated, Wanda Maximoff, known as Scarlet Witch, strolled into the room, her eyes widening slightly at the scene she had just witnessed. She swiftly brushed it off and approached Thor.

"I hope I'm not interrupting anything," Wanda said with a sly smile. Thor shrugged, chuckling slightly. In a daring move, she leaned closer and kissed Thor, matching Natasha's boldness.

Natasha watched from a distance, her eyebrows furrowed in confusion. A touch of jealousy sparked in her eyes as she watched Wanda retreat with a satisfied grin on her face.

The next days turned into a strange, unspoken competition between Natasha and Wanda, with each taking turns to steal a quick kiss from the god of thunder, much to his bewilderment.

One day, Natasha confronted Wanda. "What's this game you're playing, Maximoff?" she asked, her gaze stern. Wanda just smirked, "I could ask you the same, Romanova."

Natasha sighed, "This isn't about Thor, is it?" Wanda shook her head, "It's about us. I wanted to see who was the better player in this game."

Natasha was taken aback for a moment before she smirked, "Well, game on then." The two exchanged glances of mischief and competitive spirit, ready to continue their game.

Their competitive streak continued, each woman taking turns to kiss Thor. Sometimes they would even try to outdo each other, leaving Thor all the more confused.

One day, Thor decided to confront the women. "Ladies, I am flattered but confused," he confessed. "What is this game you both are playing?"

Natasha and Wanda shared a glance before Natasha finally replied, "Let's just say it's a little friendly competition, nothing more." Thor raised an eyebrow but decided to leave it at that.

As time passed, Thor found himself looking forward to the women's antics. Their kisses, instead of feeling strange, became moments of surprise that brightened his day.

Meanwhile, Wanda and Natasha's rivalry evolved. They found themselves supporting and caring for each other in ways they didn't expect. A bond grew stronger amidst their game.

Eventually, the game lost its competitive edge. Kissing Thor turned from a way to one-up each other to something they did out of affection, not just for Thor, but for each other as well.

Their rivalry shifted into friendship, and the kisses on Thor's cheeks became signs of camaraderie rather than competition. The god of thunder couldn't help but smile at this change.

One day, Thor surprised them both with a kiss on each of their foreheads, a gesture of fond affection that left Natasha and Wanda blushing. The tables had turned.

"Guess the game's not so fun when you're not in control, huh?" Thor chuckled, leaving the women red-faced but laughing alongside him. Their game had brought them closer than before.

They continued their little tradition, but not as a competition anymore. Instead, it became a way for them to show their affection towards each other, strengthening their bond with Thor and between themselves.

The Avengers tower was filled with love and laughter. The god of thunder, the Black Widow, and the Scarlet Witch were no longer just teammates, they became a small family of their own.

The three of them would sit together, sharing stories of their adventures. Their kisses were now signs of trust, friendship, and unity, a testament to the bond they had formed.

It was a strange turn of events, no doubt, but one that brought them all closer. The kisses of thunder, as they called it, were now cherished moments, remembered fondly.

It wasn't just about the kisses anymore. It was about the warmth of friendship, the comfort of companionship, and the joy of a bond that no one expected but everyone cherished.