The story art for the story “Changing Aspirations” by Jest. Which has oh so many fetishes in it but it can be summed up as large insertions with a bit of mind break.
 
Short summary is Mayor Mare who has been successfully running an underground crime syndicate has been caught by Celestia and now becomes her new experiment as a reward for “a job well done”. :)
 
The story can read here.
 
Changing Aspirations
 
Or here  
https://www.fimfiction.net/story/405185/changing-aspirations
 
Can’t thank Jest enough for writing this. It just about combines everything I love in a good fic. If you like the story then be sure to take a look at his patreon. All sorts of perks including early access and free short story commissions.
 
https://www.patreon.com/Jest
 
Very special thanks to Difetra for this one. This was done months ago and he waited until the story was done to release it. Really appreciate it and love how it came out!