Rainbow Dash was on her way back from a training session with the Wonderbolts. Training always left her feeling great no matter how tired she was, but now that she was in, it felt even better; though it was a little annoying now, as she about to go through all the routines again without the team. She wouldn't be practicing by herself, which she probably would have been under normal circumstances. No, she had somepony else to show the moves she had learned and take through the routines so she could reach Dash's rank one day.
Lightning Dust had been training with Rainbow Dash every day after her practices with the Wonderbolts for quite awhile. Dash had been skeptical about helping the combative, aggressive mare from getting back into the academy and possibly even back into the Wonderbolts, as she feared she might be just as big a danger as she had been before, maybe even more so then if she had the skills from Dash.
But Dash couldn't exactly just give up on somepony, especially not after she and Pinkie had managed to wrangle Gilda back into friendship. She figured Lightning Dust was probably going to end up back at the academy one way or another, so she might as well be the one to help her get there. Maybe she could get her to occasionally show a little compassion instead of always thinking with her wings like Dash herself used to.
Dash was always a bit slower during their two pony training, as she was jut getting off from serious training with the team. This fact didn't seem to holt Lightning Dust's comments about Dash repeatedly slowing down when they were flying together. Rainbow Dash felt at first that she was trying to make herself feel better by putting Dash down, but as they kept at it, realized that Dust was trying to get Dash to keep going, egging her on to make their practices a competition.
When she knew this, the routines became a bit more fun to go through, as she felt no shame in hurling small jabs back at Lightning whenever she botched a routine or was too slow to pull off a move. Dash was caught the slightest bit off guard by more racy comments, such as Lightning Dust implying that Dash was only lagging behind so she could stare at Dust's ass as they flew.
Dash quickly got accustom and began hurling suggestive remarks right back at her. The two enjoyed their time training and kept at it. On one occasion though, after they had landed for the day and were waiting for normal feeling to return to their limbs, Lightning Dust let it slip that she knew Rainbow Dash was a futa. Evidently back when they were both at the academy, she had caught Dash attempting to 'relieve a bit of pressure' in the showers.
Dash had never been shy about the extent of her gender, never trying to hide it from anypony. Being caught doing something like that was a bit more embarrassing, but Rainbow Dash could shrug it off; especially coming from Lightning Dust. What made Dash wonder however, was why she had brought it up at all. It wasn't like there'd been any need to.
When asked, Lightning just said, "Well, I just figure you being so hard up from watching me is why you take so long to catch up." Dust joked, "I'd ask you to take care of it before you get here, but then we'd have to take even longer to get started." Dash rolled her eyes, "Well it isn't like I can help it unless you wanna 'lend a hand' over here before practice every day."
"Naw, then we'd wear each other out before we got flying. How about after? Whoever flies fastest gets top~" Lightning Dust said with a wink. Dash knew she was joking, but couldn't help but blush a little. They'd both made sexual comments now and then, but never actually implied they would do anything. Dash tried to shrug it off and focus on the flight like usual.
When they were done however, Dust didn't just see Dash off with a snide comment. She pushed the rainbow maned Pegasus onto the ground in a sitting position. "Hey, what was that.." Dash's word stopped as Lightning Dust started removing her flight suit, "I finished faster, so I'm on top remember? I know you've got a horrible memory but come on Rainbow." Dust chuckled, reaching down and rubbing gently at the already growing bulge in Dash's uniform. Even Dust seemed surprised that she was already that stiff.
"I-I thought you were joking." Dash said, staring as the flight suit slid down Dust's legs, leaving her naked in front of her. "Well, what do you think now~?" Dust asked with a smirk. Dash's only response was to hurriedly get her own suit off, freeing her painfully stiff cock. Dust whistled, "Wow, I'll be honest, I didn't think it would be that big.." "What, you gonna wuss out on me now?" Dash said, half out of it being her default setting for Dust, half out of genuine fear that Dust would stop and leave her alone with the stiffness.
Dust snorted, "As it. Just gotta get it wet first." Lightning Dust got down, lowering her head to Dash's member and beginning to lick along its length. Dash moaned, shifting where she sat. She doubted they would get seen by anyone, as they were far enough out from any of the towns to avoid it. Still, she'd only ever done sexual things in doors, save for one experience when Pinkie wanted to test the limits of Twilight's cloud walking spell.
Dash grit her teeth to avoid whimpering when Dust lifted her head away from Dash's now slick member. She moved over, lining up her slit, now wet as well in anticipation, and lowered it down onto Rainbow's rod, taking it inside slowly. Dash groaned as Lightning Dust held onto her shoulders and began to ride her. The movements were slow at first, but quickly picked up as Dust grew used to the feeling of Rainbow's length inside of her.
As Dust bucked her hips, taking more of Rainbow's cock into her warm pussy inch by inch, Dash couldn't help but wonder how long Dust had been planning this. Dust moaned as she rode Dash's rod harder, pushing her hips down more aggressively. On bottom or not, Rainbow wasn't gonna just sit there. She reached up, grabbing Lightning Dust's firm ass and thrusting up to force her cock deeper into her pussy, making her moan louder as their movements began to sync up and put them at the same pace.
By the end of it they were moving faster against each other than most ponies were even capable of, though more out of both being a bit pent up than conscious choice. With both pegasi going out of their way to try and outlast the other, the fun lasted a good thirty minutes more before either of them finally broke. Dash grunting as her rod erupted with hot seed, pumping it into Lightning Dust's pussy.
Lightning Dust herself could have only held on another few seconds, and the filling up was more than she could take, she groaned loud as she went over the edge as well, her pussy clamping down around Rainbow's cock as she came, her juices washing over the futa mare's member. Both sat panting for a few moments before recovering, or at least trying to seem like they'd recovered. Both quickly got dressed so they could fly off. They didn't say anything else before they left, so Rainbow Dash wasn't certain of what if anything this meant.
But she was certain that she was going to be top next time.