What if?

The twins were lounging in their quarters one evening; Sideswipe sprawled across the top bunk reading a magazine at arm's length while Sunstreaker sat on the bottom bunk, waxing his armour.

Sideswipe rolled over onto his belly and wiggled around until his upper body was hanging over the side of his bunk, the magazine dangling from his fingers.

"Hey Sunny?" he asked
"Yeah?"
"Whadda ya think it would be like if we had a sister?"

Sunstreaker looked up from polishing his leg and gave his upside down brother a wary look. "You been into Wheeljack's moonshine again?" he asked suspiciously.
"No." Was the indignant reply, "Was just wondering, that's all."
The yellow twin paused, head tilted to one side to think. "She'd have to be tall." He said at last. "Tall but not too leggy."
"'Bout half a head shorter than me?" Sideswipe suggested.
"Yeah, about that high." Sunstreaker agreed. "She'd look kinda like us, but not."
"Same but different. Pretty and sweet, but with our sense of humour." Sideswipe flashed a cheeky grin.
His twin nodded thoughtfully. "Yeah, a real scrapper like us, a live wire, not one of those stupid damsels in distress."

Sunstreaker leaned back and picked up a sketchpad and a stylus from the cupboard built into the wall beside his bed. He balanced the pad against his thigh and roughed out the shape of a femme.

"Don't make her too dainty." Sideswipe said, still hanging upside down with his arms dangling. "She's a fighter, not some ornament."
"Mmm. What kind of alt mode?"
"Sports car, something small and fast so she can keep up with us. Ferrari maybe?"
"Yeah, that'd work." Sunstreaker sketched in the new details.

"Give her doorwings too." Sideswipe added. "Like Prowl, but not the helmet."
"Something swept back?" Sunstreaker suggested.
"Yup, nice and elegant. She's got us to compete with so she has to look good."
"Don't you mean she's got me to compete with?" Sunstreaker teased, winking at his twin and ducking as Sideswipe attempted to wack his brother with the magazine. "Visor or face mask?"
"Nah. She's got looks, let her flaunt them if she likes. We'll pound anyone who gets too friendly."

Both twins grinned.

"How do you think she'll fight?" Sideswipe asked, still watching his brother.
Sunstreaker chewed his lip for a moment. "Gracefully." He answered. "She'll be built to move. 'Cause she can't be as strong as us, she'd have to dodge the blows that we'd take."
"We'll teach her how to fight though, right?"
"'Course. We're the best there is. I don't want her to get hurt cause she tripped over her own feet running away." Sunstreaker retorted. "We'll teach her sword fighting, hand to hand, all of it. Don't want to give her a missile launcher or anything like that though, it'll add to her weight and cut down her speed and agility."

"Plus it won't look as good." Sideswipe shifted his position slightly. "Make her a medic? With us as brothers she'd have to know first aid at least." He grinned again.
"That'd mean small hands though." Sunstreaker replied, sketching in a small diagram of a hand on the top right corner of the pad.
"So? Make 'em small but strong, and slim fingers too, so she can go poking around inside us easily."
"Alright."

There was another pause as Sunstreaker worked.

"Ok, now for colour." The yellow twin announced as he snagged a small bundle of colour sticks.
"Make her a pale blue and very light grey." Sideswipe instructed.
"Why?"
"Well, we've both got strong colours, red and yellow. This way she looks different to us and we don't all clash."
"Sounds good." Sunstreaker nodded, selecting the appropriate colours and adding them in. He held up the finished sketch for a final inspection before handing it to his twin for approval.

"Niiiice!" Sideswipe grinned, still upside down and twisting the picture this way and that to get a better look.
"That's enough ogling our sis!" Sunstreaker mock snapped, plucking the sketch pad from Sideswipe's grasp and earning himself a whap over the head from the rolled up magazine.
"What are we gonna call her anyway?" Sideswipe asked. "We can't just go around calling her 'Sis' all the time."

"Well,my name isSunstreaker, your's isSideswipe, so she can be…Moonlight." Sunstreaker said. "That way, she's got a link to my name, Sun and Moon being opposites, and it rhymes with your name too."
"Moonlight." Sideswipe repeated, trying out the feel of the word. "Yeah, I like it. Moonlight it is."

Fin