Umbra gently nuzzled at her magic partner. "I had a lot of fun, so much... but I really should go."
"Aw." Starlight willed her book shut, floating it towards a shelf. "Do you have to?"
"We both have our responsibilities." Umbra stretched languidly. "And we both have something to look forward to. Top or bottom, our next match will be... interesting, hm?"
"One word for it." Starlight raised a hoof to her chin. "Oh... should I... not with other ponies?"
"Why not?" Umbra snorted softly. "We're not officially 'a thing'. I can't claim you like that. I already have a thing! A lot of things! They have more right to be angry at me right now." She looked off into the distance. "I bet some of them are trying to figure out exactly what I've been up to, but I also guess they can take a few guesses..."
Starlight darkened at the thought. "I don't want to get you in trouble..."
"Me and Cadance and Shining are officially open. They're closed with each other." She gestured in the air, explaining the facets of the polycule. "But share access to me. That's where I left that, so if they want to take umbrage now, they'd better start from the understanding that we are not a closed thing, but maybe could be?"
She went stiff suddenly. "Dirty p-pool..." She spread her wings, but her muscles were twitching lightly. "Mmmf, not... fair."
"Are you alright?" Starlight bounced to her hooves. "Can I help!?"
"They are exacting their terrible revenge." Umbra forced a smile. "And I deserve it."
Starlight gave a soft huh. "You look like you're enjoying that as much as you're not. Maybe this is exactly your kind of game... Either way... thank you for sharing." She offered a hoof, meeting in a firm clop. "I will tan your hide next time, so bring your A game."
"You know it." With all her things gathered, Umbra saw no more point in delay. "They must be missing me. Take care." She melded into the dark of the ground and was gone, zipping back towards her family.
Sure, the happy couple were happy coupling at her, and not even trying to hide their broadcasts, but she had literally just done that to them, so she couldn't rouse the will to even be angry at them. Let them enjoy their little revenge. She had more immediate things to get back to.
"Mother." Morning nodded lightly at Umbra. "It is good to see you back."
"Umbra!" Shifting was far less reserved about it, tackle-hugging Umbra tightly. "Did Starlight give you a run for your money?" Shifting was Starlight, grinning at Umbra. Her mischief turned suddenly to surprise. With a new green rush of flames, she returned to her crystal bat self. "We... should talk."
Umbra hmmed? "Is something wrong?" She went past Shifting to smooch the top of Morning's head. "Have you been good for your mom?"
"You weren't here." Morning inclined her head. "How can I be good for you? My homework is complete."
"That's good, very good. I meant her, silly." She pointed to Shifting. "She's your mom too."
"She's on probation." Morning turned half away. "We're working that out. I will keep you updated, mother."
Shifting laughed tensely. "That's between her and me. Work in progress... But we do need to talk."
Umbra dropped her saddlebag off and came back to Shifting. "I always have time for you. What's up?"
"This way." Shifting led Umbra outside the house, waiting for the door to close before she sighed. "I thought we were a thing. You know... fiances?"
Umbra sat down, still a moment before it clicked. "Shoot... We didn't set that boundary, and it's at least as much my fault if not more. I'm sorry. You can be angry at me now... But I am curious, what set you off?"
Shifting raised a brow. "I was Starlight and you felt something besides just friendship at her... It's hard to sneak cheat on a changeling!" She stomped a hoof. "And I don't even like that kind of love! Ew..."
Umbra raised her hooves protectively. "Not sneak cheating, taking that blame right up front. You have all the right to be angry with me, but I'd like to fix it so it doesn't happen again."
"And how do you do that? I thought I could trust you." She crossed her arms with a mighty pout.
Umbra curled her hooves back on herself. "By actually setting those boundaries. I do not break a promise that's made. Now, you know I'm already part of a thing, right?"
"Starlight is not Cadance or Shining Armor," huffed out Shifting. "And still..."
"And still we didn't set the rules. So let's set them, nice and clear." Umbra drew a line in the dirt. "I did bad, no arguments. Let's never repeat that."
"Stop being reasonable!" shouted Shifting perhaps louder than she intended. "Let me be angry... You did something worth being angry about. It's not fair you're trying to adult-smother it..."
Umbra closed her mouth and flopped over. "I am ready for my punishment."
Shifting nudged at the prone Umbra, the contact not qualifying as a strike on any level, barely rocking her. "Ugh... Being reasonable can be a pain too... So...." Her cheeks began to warm. "Why were you doing things with Starlight, and not me? Did you think I... wasn't available?" She glanced away. "I know I'm not that eager..."
"That was part of it." Umbra gently pawed at Shifting's hooves, playing footsies with her, still sprawled on the ground. "The other was wild happenstance. I realized ponies just didn't understand a kink, so I showed it to her... and we both had a good time, and I hurt your feelings and ugh I am the worst."
"Let me say that," huffed out Shifting, tail lashing agitatedly. "You gave a lesson on naughty play?!"
"Yep."
"Is..." Shifting rolled a hoof in the air, pawing at nothing. "Do I know this lesson?"
"I don't know, but I doubt it." Umbra rolled up to upright. "I think I just invented a kink for the world, which is something to be proud of... but not worth the price if you're mad at me."
"I am mad at you!" She swatted at Umbra, a light thwap. "So... boundaries. We are a couple. No playing with other ponies!"
"What about Shining and Cadance?" Umbra waved off towards the North. "No them?"
"Nnng... I already knew about them." Shifting perked her ears. "But you don't play with them.... much? Do you? I don't... Do you?!"
"I got real busy..." Umbra considered a moment. "I want to make it up... What can I do? Not a gift, unless you really want something, but something I do for you. What do you really want? I owe that and a lot more."
"Is she still my maybe mother?" Morning was peeking out the door to the house. "Or should I eject her?"
"You will do no such thing!" Umbra circled to be in the way between the two. "I was the bad one. If anyone was being kicked out, it'd be me."
"I doubt that." Morning was unwaving in her faith. "Very well. Shifting was preparing dinner, but you arrived... Shall I fetch you something, mother? I can let you have mine."
"You will enjoy your portion. That's an order." Umbra turned back to Shifting. "I'll order something. My fault for showing up as late as I did. Besides, I don't deserve Shifting treats right now."
"Stop being reasonable." Shifting nipped at Umbra on the way past. "And dramatic. I'll have a portion ready..." She slipped inside to make that happen.
Umbra gently patted the top of Morning. "I don't deserve her."
"Of course you do." Morning headed inside. "One day, I will vanquish and conquer a pony of my own. They'll make me dinner."
Umbra followed after with a soft huff. "We're going to have to go over that... In the meanwhile, your homework is done, good. Are you done with your umbrum lessons?"
Morning smiled a victorious predator smile. "He said that I had a warrior's heart. Charmed, but I'd remember if I had a valuable heart. I'd ask you to seal it in crystal as a keepsake." She hopped up at the dining room table to have herself a seat. "We have accomplished our goals."
"We have!" Umbra stepped up to sit across from her child. "Which means it's about time to head home with our prizes."
Shifting came in, setting down a few platters with her wings, giving a final little fluttering flap with the last settled in place. "You never said how Luna did with your book. Is she a shadow wizard too now?"
Umbra softly hummed at that. "Now that you put it that way... She was a wizard before I got there, for over a thousand years, even if most of those were spent in timeout. And she is princess of the night. It shouldn't be a surprise that shadow magic came easily for her. As difficult as it was to grapple for her sister, she eagerly devoured it. 'Shadow spells that do good things? How novel!' she had said, and ate it all up."
Morning frowned a little. "You are emboldening your rivals, mother. Why?"
Umbra waved a hoof at Morning in a little wag. "A favor given today is received tomorrow. Besides, we're more likely to be on the same side than not, and I'd rather have my shadow magic used for me."
Morning's concern faded into a smile, rubbing her hooves together. "Brilliant, mother. You are arming your servant. I see the wisdom in that. That will free you to use your magic to other ends at the same time."
Shifting reached with a wing, gently patting the foal. "You are amazing to listen to at times, now, everypony eat up and enjoy."
Umbra took a cheesy bite of dinner. "Mmm, this is new, and good..."
Shifting took her own toothsome chomp. "Canterlot has different things in its market, and while you two were learning all kinds of magic, I was picking up some local recipes. I'm casting my own spell on you both, and you're helpless to resist it."
Umbra licked some of the cheese clear of her snout. "I surrender to your culinary skills, which I didn't know you had a lot of, but you've gained a skill while I wasn't looking. Sneaky thing."
Shifting's tufted ears wagged. "I can learn a thing or two. Not just you two are expanding their horizons."
Morning didn't respond, too busy viciously tearing into her food. She approved of it, at least was clear, ripping it to shreds between her sharp teeth and voracious appetite.
Shifting watched her with a little smile. "It's not hard to see when you got it right with her. So, when are we heading back?"
"I'm done." Umbra clapped her hooves, but was still nibbling at floating food. "We go back when you can say the same. You waited patiently for me, and put up with me being a dingus. This trip is now yours. We go back when you want to go back and not a moment sooner."
"What power." Shifting leaned in, licking a cheesy spot off her girlfriend. "It'll go straight to my head... Alright. I'll have a plan ready for tomorrow. For tonight, we just enjoy being a family."
"I'll drink to that." Umbra willed a bottle over to pour two glasses.
Morning was watching intently.
"Something wrong?"
"You forgot a glass, mother." Morning pointed at the two glasses, clearly missing the third.
Umbra popped the cork back in place. "This drink isn't for foals, which you are. I care about you, so no."
"What could you be drinking that I would not tolerate?" Morning frowned with thought. "I'm tough."
"I'm certain you are..." She tapped the glass. "This is a poison. Adults drink it as a sort of game." She wasn't even lying! "Finish growing up before we sabotage things."
"A curious game." Morning was looking at the bottle of poison. "I don't need to prove myself that way. The broken bodies of my enemies works better than harming my own."