I give the faces of the characters a Mass Effect: Andromeda out of five.

If anyone is interested, the artist has written a full story based on this image and the idea. It starts with the story leading up to the above image, then goes into full sex between Barb and Dusk, and ends with a bit of humor.  
How To Discipline Your Dragon  
I don’t know if it’s to your liking if you have a spanking kink, but it’s pretty well written and entertaining.

Happy days! Barb and spanking together at last!

Oh look, it’s Sheldon punishing Amy.

From Source
 
As his hand collided with her purple rear, an audible and loud smack resonating around her bedroom, the dragoness tried to stifle a moan but ultimately failed.
 
 
“HNNGH-AAHH!”
 
 
“…”
 
 
Dusk gulped as his hand trembled in the air, looking down at his number one assistant, his best friend and his legal charge pant on his lap. He felt his brow become damp with sweat as he looked back from her head to her now reddened rear cheeks as he tried to process what was going on.
 
 
Applejack had come round earlier that day too, yet again, complain how he had caught Barb and Rainbow Blitz making off with his cider and demanded that Dusk do something about it. Whilst Blitz was being dealt with by parties unknown, Dusk pondered on how to punish Barb. He had never really had to do it whilst they grew up, as Barb was almost perfect under his care. But as of late, she had gotten a tad unruly. No thanks in part to Rainbow Blitz.
 
Despite having a relationship akin to brother and sister, Dusk Shine was the legal guardian of Barbara and he knew it was down to him to decide on a punishment. After spending hours trying to work out a good way to discipline her, he remembered about how when he and his sister, Gleaming Shield, were young. Their parents would give them a spanking when they had done something bad and at least for Dusk, this was enough to set him on the near straight and narrow.
 
 
So, naturally, he saw that this the best way to teach Barb a lesson. Age not being an issue to the young stallion.
 
 
After reading a book on how to spank a naughty foal, Dusk entered Barb’s room and the punishment began on her sofa. However, much to the stallion’s confusion, Barb would keep making the most… erotic of noises when his hand collided with her plump, purple ass and he struggled to keep his blush from forming on his face as the blood began to seep down into his trousers as the young dragoness moaned softly into the incoming strikes.
 

 
Also on my Tumblr: jimjamdoodles.tumblr.com/image…
 
No speech bubble version: i.imgur.com/2MNfWyy.png
 

 
Art is © to me  
MLP:FiM and characters © to Hasbro