your horse belly expands to giant proportions, way too big for one baby......
boom! horns explode from both sides, to save your own life you instinctively grab the small horns and twist each one, they snap off. without the tool for their none-too-gentle exit from their mother, they are forced to be born the conventional way. it was pain beyond any imaginable, but it wasn't as bad as girls said it was, maybe because of your mare rear. as the first maimed unicorn baby comes out you cradle it in your arms and let it suckle on your teats, but you do not have much time for maternal affection as the second one was on its way out, when it was safely out you see it bleeding from its snapped off horn, you know it cannot be saved but you're the one that killed it in exchange for your own life, as it bleeds out you break down crying, as you're crying the first baby continues to suckle on your teat, strange since that goat kit told you they kill their mother. THE GOAT KID! you look over in horror at him, he has a shocked expression on his face, "congrats, you're the first mother to a unicorn to survive their birth, hey, shouldn't you be bleeding from those holes?"
you're mot bleeding, your mythical centauress form seems to have a fast healing factor. your remaining baby stopped suckling and started to nuzzle its horn, it then pressed its head to its horn and it reattached like magic, there your baby, a beautiful unicorn colt. your beautiful unicorn colt. The centaur returns, but it no longer needs its disguise since you know what it is it just stared at you, its horn glinting in the light. it just turned away and clopped into the distance.
another centauress clops towards you, "you're really brave, you know that?" she had a soft sultry voice, and the male part of your female brain noticed she had HUGE breasts and some great kissable lips, "thanks" you reply meekly after glancing a couple times at her huge bust, those were massive, at least an o cup. you pull her into a tight hug, your average sized breasts rubbing against her large water melon sized ones.