Traditions (Lucy/Natsu/Gray/Erza)
At first, Lucy had started dating just Erza, but the fact that her girlfriend's other two partners were in their same team meant that, inevitably, they would form bonds. And it just so happened that those bonds developed in a romantic way.
Date nights were interesting. Sometimes they would all go out for dinner and a movie, other times it would be just her and Erza going shopping and then taking a break at the redhead's favorite pâtisserie.
Or she and Gray would go to the zoo, so he could study the animals to improve his ice creations.
Or Natsu would take her to the carnival and try to win all the prizes just so they could rub it on Gray's face.
Yet, even though she loved her partners and appreciated all the time spent with them, Lucy couldn't stop a feeling of doubt from crawling up now and again when she was reminded that they had known each other for a longer time. They had been together for a while before the blonde joined and it made her feel...a little insecure. As if she were the least important one in their quad, so to speak. Maybe even, in a way, expendable.
It was on a chill autumn day that her lovely partners shattered this misconception. Lucy was sitting with Levy, talking about the latest read from their Book Club when the ice mage went to sit in front of her. "Hey, Lu, what ice cream flavor do you like the most?"
"Chocolate, why?"
"Just wanted to make sure we get everything we need from the store before going to your place." He noticed her confused frown and, with equally furrowed eyebrows, Gray asked, "Natsu didn't tell you?" she shook her head. He immediately turned to reprimand them.
"Wait, what were we doing today?" Erza approached and took the seat Levy had just left.
"Today's the anniversary of when we three started dating and we celebrate by making junk food from scratch," for a moment, that annoying feeling took root on Lucy's chest, but Natsu joined them to rectify their mistake.
"We normally do it at Gray's apartment, but we thought it would be better to do it with you because...well," they turned a little sheepish, "we want you to be part of these traditions now."
The feeling in her chest was crushed by that statement. The blonde pulled them all into a hug and insisted on going along with them.
That day, she built up the courage to be honest and tell them about how she had felt. But that was long ago, now Lucy rarely felt doubtful anymore and, on the few occasions when she did, they always made sure to prove her wrong.