@Little Ribbon  
Fluttershy getting tickled at every red traffic light? I approve!
 
Hmm, if, as I am guessing, this is Pinkie Pie’s car…perhaps it is fuelled not by petrol, but by laughter? So Pinkie always has to take a passenger for a ride, and she finds tickling them the easiest way to refill the car’s energy reserves with laughter? ;D
 
Flutter’s soles and toes just look so wonderfully soft and ticklish here, and the tried but true method of using a car’s seatback as a makeshift stock is just a deliciously Pinkie Pie thing to do.
 
Caroo, some day I have got to commission some tickle pics from you - man, you’re killing me with your art! :D

@Little Ribbon
 
It’s quite abusable, yeah. Somehow didn’t occur to me that they may be in motion. Good thinking.
 
And for what it’s worth, me being the commissioner and all, yeah, she gets quite loud. Which is cute. And thanks for the outfit praise, the anthro “design” (more like dressup) is courtesy of meemee too.

@Caroo  
It’s my favorite improvised stocks method. Cute and playful thing to do. Maybe Flutters gets tickled at every red light on the trip.  
Fluttershy looks adorable in that outfit too.
 
 
@Background Pony #669B  
I’d guess it’s just an effective way to tease her, especially if she has a loud laugh

@Background Pony #9545  
Applejack would say the same about a Pinkie Promise.
 

Questionable? Maybe it is suggestive? There is no adult for questionable tag.

Take it they are in a Ford Feet-sta?

Look like fluttershy miss one too many parties. You don’t refuse a invitation from pinky pie😏

@Background Pony #B5F8  
This, and maybe color??

D’awww, Flutt’s toes are squirming so much~ <3

Why not have Pinkie lick Shy’s soles.

@Caroo  
Hmm Man they must have a TARDIS in there backseat then XD

@Background Pony #07F0
 
Well the image was referenced by a real life pic. So it should be quite real. :)
 
https://www.dropbox.com/s/9p2zztrpau9any3/1702293.jpg?dl=0

Do you also see fluttershy as a “ticle masochist”? Or is she more the mild playful type that only enjoys it until certain points? Is just that some other stuff of hers kinda hints that

This seams both cramped and uncomfortable. I mean have you seen the leg room in the backseat of modern cars? Guys in the Phantom Zone would have more space than is back there.