@Alara Rogers  
Yes, he would give flowera to Sombra and he would give flowers to Tirek, especially Discord, especially in Equestria. He gave Twilight a necklace shaped as a heart. In our world this would also imply a romantic feelings. But it wasn’t. Discord gave two bouqets of flowers, which imply that it wasn’t just for her. They also weren’t red roses to mean anything.  
It also not true that you can’t give flowers to your female boss for screw ups. Where I live, people give flowers to anyone especially on “international women Day” at work. College students give flowers to female proffessors when they agree for additional exam.  
It doesn’t mean anything especially when Discord betrayed her just few hours before that scene and casually was playing with Luna, Celestia and Cadance window icons like they were just some puppets. Discord even remotely liking Celestia or Luna or being their friend off screen is just a headcanon. Not to mention his attraction toward any. Discord is just her subject who interacts with her when she want something and give him orders. Giving flowers her and her sister can only imply him wanting to apologise and become their friends AT MOST. Thinking that he want to become a romantic partner is the biggest overstretch of that gesture made only by the shippers. He is as mush close to Celestia as Rainbow Dash is close to Luna.

@Background Pony #8C58  
I reiterate: You do not give flowers to your boss to apologize for screwing up. Men give flowers to women to apologize for screwing up in the context of male/female relationships (past, present or future), or the context of family. A man would think twice about giving a platonic female friend flowers as an apology because she might take it as romantic, and a woman who has no romantic feelings for a man she is not related to would probably be bothered by getting flowers from him.
 
So yes, it is an apology, but the method of apology indicates that they are, or were, or Discord hopes for them to be, romantic partners or close friends, or that they are family of some kind. Imagine that Sir Discord from the comic book mirrorverse wanted to apologize to Good King Sombra for something. Do you think he’d give flowers? Do you think that, if he did give flowers, half the Internet would not assume this meant shipping was in the air?
 
It’s not a romantic gesture, it’s an apology. But it’s a kind of apology that’s only given within relationships that are familial or could be romantic or are at least very, very close. And while one could say Discord gave flowers inappropriately because he’s chaotic and ridiculous, Celestia does not react like the flowers are inappropriate.
 
But since the original subject here is Discord/Tirek… Discord’s reaction to being given the amulet, and then being told the amulet is worthless, is also a reaction that one wouldn’t expect between mere allies or even platonic male friends. That has shipping undertones as well. So I’m certainly not trying to argue against Discord/Tirek, at least as something Discord was hoping for. :-)

@Alara Rogers  
those served just as an apology to Celestia and Luna, nothing else. Jeez no wonder no one giving flowers to anyone these days

@Background Pony #8C58  
Not sure I’d agree with that. (You don’t give your boss flowers to apologize for screwing up. That kind of apology gesture is specific for male-female relationships. Doesn’t have to be romantic – you might apologize to your mom or aunt or sister with flowers – but honestly, it usually is an apology gesture made in a relationship that’s either romantic now, was once, or the guy is hoping it will be someday. Plus, flipping out and acting like the fact that this one guy broke out of jail is the WORST POSSIBLE THING, much more upsetting than Tirek or Sombra were, and then releasing him on parole yourself, is a lot more consistent with “that guy is my ex” than “that guy is really totally evil” or “that guy is just an annoying jerk and I think he could be redeemed”. So I think there’s plenty of evidence that there was something going on between Discord and Celestia, at some point.)
 
But yeah… the fact that Tirek actually reciprocates Discord’s touchy-feeliness and voluntarily touches him is significant. No one touches Discord on purpose except Fluttershy, and one time Pinkie did. Given that Pinkie is totally tsundere about Discord (one episode she yells at him and assumes the worst of him, the next she’s hugging him and volunteering to take care of him while he’s sick) and that everyone seems to think there’s something going on with Discord and Fluttershy, and that the title “Lord of Chaos” does not particularly imply “purely masculine straight heterosexual” :-)… yeah. I ship it. In a twisted, fucked-up, Tirek-seduced-Discord-and-threw-him-away kind of way.

well you can hate it or not but you need to admit that discord had more chemistry with Tirek than ever with Celestia (At least before betreyal). Discord COULD have been his queen if Tirek ever liked him in the first place, i mean he did betrayed Fluttershy for him xD

@Background Pony #BA23  
that
 
Sounds like a fusion of disco and techno :D

Should have called it Discotek