The essence has been given willingly, a cinder that burns bright with hope. Your student has done well Celestia, though let us hope that the Vessel will continue to grow steadily as the stakes are now that much higher.
You blushed deeply as Twilight explained in extreme detail what your actions have brought about, besides creating a Cinder of hope. "Wait... so let me get this straight, because we've well... been intimate, you're officially pledged to become something called a lead mare in my herd?"
Twilight giggled and nodded. "That's correct, which means you're now officially able to add mares or stallions to your herd if they'll let you and get your lead mare's approval." She explained this as if quoting it from a book word for word.
You blink twice and sigh. "Twilight, while I think it's lovely that you approve of such a thing, I'm not sure I really want to start a herd or anything like that... I mean, I'm not exactly sure how this will affect my powers yet and I don't want to hurt a bunch of ponies’ feelings just because I'm not actively seeking relationships."
Twilight blushed deeply, realizing that she'd pretty much put you on the spot by doing what she did. "I-I didn't... sorry Spirit." She said with a blush as she cuddled up to you.
You didn't really feel that it was fair to her to say anything more about what had happened, so you pulled her close and gently held her in your arms. As the pair of you drifted off into sleep, the warmth of each other’s embrace did not seem to fade, even as sleep took ahold of you both.
The Vessel's Inner World
Your eyes opened to reveal that you were sitting in what should have been the middle of the field that was contained in the Inner World of the Vessel. You'd been here multiple times and every time you visited something seemed to change. As you looked around, you saw something that explained why you were in a room that looked like it belonged to the Golden Oaks Library on a more elaborate scale. Twilight was cuddled up against you, seeming to be asleep.
Snuggling up against her was Dream. "Love you, purple mommy." The filly said softly, which caused Twilight's eyes to jump open, as if not expecting somepony else.
"W-What? Spirit where are we?" She asked, slightly panicked as she stood up quickly. This caused dream to flop onto the bed a bit due to her support vanishing. As Twilight scanned the surrounding area, she started to notice odd things. Like the fact that everything after a certain distance was covered in a thick fog, not to mention that this room of the library wasn't at the proper elevation.
"S-Spirit where are we?" She asked again, confused as Dream opened her eyes. Before either you or Dream could explain, another voice entered the conversation.
"I see. This does explain the sudden increase in Sir Spirit's magical reserves." The door to the room had opened, revealing Princess Luna. "I must admit that I was curious as to how this room came into existence, and now that I know I feel... I believe the word is jealous?"
Her admission caught Twilight off guard and forced her to blush heavily, before sputtering and looking at the Lunar Princess.
"Good evening Princess, I believe you've already met my ward, Twilight Sparkle." You said to Luna somewhat formally. You stood up and your usual outfit was colored lavender this time, as if representing the Cinder of Hope that you and Twilight had just created.
This caused Twilight's eyes to widen as she put two and two together. "So, this is the other world you talked about? The one you go to when you sleep?" She asked excitedly, noticing with a blush that his outfit matched her coat color.
"Indeed. This is the Vessel's safe haven for it's commanding spirit. Important events that happen to the Vessel will add more objects to the landscape. When a Cinder of Hope is born, the ward responsible for it gains the right to access the safe haven if they fall asleep near the Vessel." Luna explained, as if predicting and answering the question on both Twilight’s and your own mind.
"Well, that explains quite a bit really." You admit with a blush, as the clothes the Vessel usually wore suddenly turned back to their original coloring, although there was now a six pointed purple star on the front where the pocket was. This earned a blush from both mares and a confused expression from Dream.
"Does this mean I have two mommies now?" She asked, causing Twilight's eyes to go wide.