This story is set in the world of Damaged's stories of Softy's Kindness and Stripes Loyalty. It is published with the kind permission of both Damaged and his patron, who commissioned those stories and this should be considered a non-canon side story to Damaged's tales.
Thunderlane has two wonderful pets. Stripes and Softy, aka Rainbow Dash and Fluttershy. Things couldn't be going better, particularly after a truly wonderful date with Softy. However, wary eyes are casting concerned gazes toward somepony who has two of the most important ponies in Equestria as his lovers.
Tagged Teen due to mature themes without any mature actions
Chapters (1)
Nice work, and of course it'd be Luna who'd have concerns, or at least the one that would be upfront about said concerns. And of course she's played, no surprise with her, but her sister... I'd be a bit surprised to hear that she has. Oh, one thing I would've done different/added, very minor, but if I were Luna, I would've told Thunder how to reach her via the dream realm in an emergency, since its likely the fastest way to reach her should it be necessary. Still, just a very nice story, glad to read it.
8085799
In Damaged's last installment there is a piece where Celestia recognizes the brand of collar Fluttershy is wearing. So, either Celestia has played as well, on one side of the leash or the other, or she is close to someone who has. I like to think that Celestia plays discreetly, when she can, on both sides of the leash.
8085810
Luna is a difficult case. If I had to make a guess... I'd say she's probably a submissive. She's desperate for love and affection and trust, and she has an unhealthy need to castigate herself for what happened in the past. Unlike with Celestia, she also doesn't seem to be that well-adjusted to being a princess at all. She's a lot more fragile than Celestia but tries to distract from it by being all serious all the time. Luna would probably love the chance to just... let go. Let herself fall into the hooves of somepony she deeply trusts, because after what happened with Nightmare Moon, she'll always have difficulty trusting herself.
Chuckle, Thunder didn't exactly get the answer he wanted in to that last question.
Fanfanfics
I thought Dash was pregnant already