Both my OC ponies together, Unit #3 and Pretty Princess. The idea is they are 'whipping their tail back and forth.' (thanks to ONE SKIT from Ponies: The Anthology 2!) I don't think I captured that specifically in this one. I do however think the art turned out nicely. Especially Pretty Princess's eyes, I like how those turned out :3

Mature for...well, mostly because I dunno how pony rump is received, but #3's Cutie Mark is definitely mature c.c