Caisson was a big colt.

Like, really big.

Folks around Ponyville said that there hadn't been a colt in their senior-year of highschool as tall and strong since Big Mac, and Caisson likely had him beat! Normally, this would be a source of pride for a farm-colt in Ponyville, but he's always had the sneaking suspicion that the fillies in his class prefer the frou-frou athletic pegasi or slender unicorn stallions that everypony sees in all the fashion magazines from Manehattan. Why else would they blushingly look away from him every time they made eye contact?

His body-type is anything but that of those svelte fashion-model stallions: he's a walking tank, standing a few hooves taller than anycolt his age, with muscles that could rip a tree-stump from a frozen field.

Worse, he still seems to be growing! It's the first day of the new school year, and it looks like over the summer he's left his buddies even more in the dust in the height and brawn department.

Because of this continued growth, Caisson has yet to receive a custom-fit harness; that's a big deal for working farmcolts. Since they'll spend hours every morning before school working the fields, and hours every afternoon after school doing the same... a well-fit, comfortable harness to distribute the excruciating load of pulling a plow or a wagon is a must.

Thanks to his body, Caisson has to make-do with a jumble of adjustable straps, buckles and tie-downs... a confusing mix that requires the help of another pony to strap in.

A harness-buddy is a special thing among pony-folk: there are lots of straps that go into (and around) very private places. Depending on the circumstances it can be professional, awkward... or exciting.

And it just so happens that since his younger sister has now started in her freshman year at highschool, they'll both be getting home to the farm at about the same time.

She'll be strapping her BIG brother in.

Will the two be able to resist any of the hormone-fueled temptations that might arise when in such intimate circumstances? Nope.

My entry to the Incest is Wincest Slice of Life September Contest

Contains: MF / teen-foalcon / incest / size-difference / rut and estrus / excessive-cum / cum-inflation / pregnancy

Inspired by and/or set in the wonderful universe created by Admiral Biscuit's fantastic story Mares Complaining About Penises

Huge shout-out to AJ Aficionado and Admiral Biscuit for their help editing.

Cover art is an edit of a piece by Keep On Hatin