Well, now this is just a suggestion, how about diapered background ponies, whether or not they are adult or foalified I'll leave up to you. You could try combining all three like say Soarin and Twilight with one of them diapered, or maybe Soarin and Rainbow Dash, there's a lot of possibilities. Sorry if this isn't helping at all. Should I try to narrow it down?

Thinking more like single pony things, things the pony could be doing in the image, stuff like that. But that's good how you're suggesting it now though, broad, very broad range of things that gives me a lot of play to work with. I just wish more than one person would suggest stuff.

Something I've not seen very often is characters being hugged, cuddled, nuzzled... that sort of stuff.

Well the reason I've not done anything like that yet is because I don't believe I have the ability to do that and make it look halfway decent yet. I still need to work on the basics. (As you can probably tell) as I'm not really the best artist around lol.

That said, I do want to experiment with that sort of thing, so I will likely try to do something involving that in the future, however it will likely start as simple nuzzles and such and work it's way up to contact/hugs/cuddles. It just seems like every time I try to do anatomy like that involving contact between two characters it comes out weird or misshaped, so I scrap the images and don't ever finish them/upload them.

Oh.

Anyway, trying new things, things that are much more complex and hard to draw, is a good way to practise. Even if you don't believe in your skill to draw something more complex, you could at least try to sketch something like that.

People can learn faster when they try something much more complex and harder.

: )

Well I for one, think you should draw a background pony in diapers. Which pony you ask? Well I'll leave that up to you Midnight :P