Tidko was wandering around the castle, in look for the twins. She didn't have any actual things to do today, so she could just chill out. However, she hates being alone, especially in a cold and mostly dark castle. Hectic servants and mostly silent guards make poor company for a day-off. She needed someone nice and cool to be around. Someone she considers her family.
While walking across just another hall, Tidko have decided, that she is tired of just looking around. If they are behind the closed doors - no way she will ever find them. Royal castle keeps many secrets, so most of the doors are closed, and with fairly good sound protection, to prevent guards and servants from hearing things they aren't supposed to hear even on accident. Guess she can just ask? Luckily for her, royal guards just stand near almost every corner of the castle. With the closed helmets to hide their boredom, as castle shifts, unlike city ones, are all about standing still for hours.
Nightstalker aproaches one of the guards.

- "Where are they?"

Guard keeps silence for a few seconds. Probably... processing her request?

- "Where... who?" - seemingly confused.
- "You know who! Eiris and Alen! Have you seen them? It is important! I know their schedule, they must be somewhere in the castle!"

Guard keep silence for a few more seconds, giving quick looks left and right.
Then breaks the silence.
- "Alright, important, I get it... Well..." - his voice is much more quiet now. A bit anxious. "- I remember them coming upstairs. If I were you, I would look in one of their bedrooms. Probably having some... important royal talks..."
- "Important royal talks?" - Tidko raises their eyebrow.
- "Even if I knew - still wouldn't tell... Not even to you. You know what Supreme Judge does to guards that gossip about royal business too much..."
- "Hey, that' not...! Ugh, fine..." - Tidko snorts. But then forces a smile on herself - "Thanks for the help!"

Nightstalker turns around and and moves at a wast walking pace upstairs.
- "Hmm..." - takes a look around the royal bedroom doors. Goes to the Alen's room and knocks a few times, after which immediately pushes her ear against the door in hope to catch at least some kind of response.
- "Eiris? Alen? Are you here...? May I go in...?"

Well, some sound she can certainly catch through the door. Room isn't empty after all!
- "Oh, hey, that's Tidko! Should we let her in?" - well, that is most certainly Eiris' voice, muffled by the thick door.
- "Well if you want her to see you like that..." - oh, and Alen is here as well.
- "It's fine, she is our half sister. A family member, you know!" - Eiris voice get's closer - "Just a second, I'll open the door!"

Clicks of lock rotation, and door gets... slightly open. Just enough for the Tid to jump in, and immediately shut the door behind her, before anyone sees.
Yep, that is Alen's bedroom. Unusually bright, made mostly in white and pink colors. Which is quite a contrast to the rest of the castle, where most of the surfaces are covered in black marble, making it extremely dark, like a cave or a mine.
Both of the twins are here, and... naked? Eiris stands near Tidko leaning towards the wall, while Alen sits on his bed, looking at the floor, then moves his eyes to Eiris, and then finally to Tidko. It's not like Tidko haven't seen them naked before, yet she blushes as her eye catches a bit of semen dripping from Eiris' pussy.
- "Umm..." - nightstalker surely wants to say something, but it's a bit hard for her to find her words. - "Did... did you...?"
- "Yes, but... we usually don't talk about it... You know... Not great for our... credibility... " - Eiris rolls her eyes
Alen giggles
- "You've done much worse things for your credibility than riding your twin brother, ya know..."
- "It wasn't me, it was that crazy bitch Rose!" - Eiris gives her brother an angry snort.

Tidko continues to stand still, speechless and blushing. Probably not even catching the arguing between twins, as her thoughts are still stuck on one direction.
- "I... umm..." - her voice gets more quiet - "I'd love to..." - her hips clenching. - "... have too..." - nightstalker bites her lower lip and closes her eyes, like she is scared of what she just said, yet her tongue goes alongside other parts of her mind.
Suddenly twins ceased their talking, looking at Tidko. Yet as her eyes are closed, she probably can't see it.
A few moments of silence. Then Tidko feels Eiris' hand at her shoulder and opens eyes to have a glimpse at her. She sees... a little grin at Eiris' face.
- "Are you sure about that, Tid? There won't be a way back..."
Tidko feels like burning from the inside. Covering her cheeks with her hands, staring at the floor.
- "Y-yes... I'm... very sure..."
Alen gets up from the bed, aproaching Tidko from the front. Tidko takes her eyes up to look at his face, but then her eyes slide down across Alen's naked body, stopping at the cock, that seem to go noticeably bigger since Tid announced her wishes.
- "You know... If you want to - I'll gladly accept... You are a nice girl and... I am glad you have such interest in... us..."
Tidko, looking extremely anxious, and being surrounded by two sexy dragons, bites her finger on one hand, and stretches the other hand forward, to touch Alen's cock with her fingertip.
- "I... yes, I... I love you... I love you both so very much..."
Eiris bends a little bit, so her face will be at the same height as the face of the nightstalker and speaks quietly:
- "Want to do it right now...?"
- "Yes please..."

Absolutely Awesome Artwork (AAA) by a wonderful  Disease_dis
Seriously, she is a great artist, give her some love 💜

Featuring Tidko