Magical stallion mpreg

I have an idea (I can't believe I'm making this up.)
What if the ritual involved taking certain magic supplements before hand, about once a day for a month. A month to show if the two stallion's really want to have children together. These supplements would form a womb similar to that of a female's inside the the receiving stallion, and could only be accessible by an opening shaped like a vagina's formed inside the anus. His behavior would also change a bit too, acting a little more feminine and flirty giving him the desire to be bred, but still remaining himself. On the last week before conception the receiver would take the remaining supplements causing the womb to start creating the egg. On the night of conception the giver would take a magical supplement meant to mix with his sperm to fertilize this particular egg. If the egg is not fertilized or the user stops taking the supplements, the womb dissipates and the stallion returns to normal. However, after conception the fertilized egg seals the deal, and the womb acts like a normal womb for the next however long it is until birth, no longer needing to take supplements. During those months the stallion still has the personality effect of the supplements, acting more motherly. When the time comes to give birth, the womb comes out of the stallion along with the child, detaching from the host. The remaining magic seals up the opening as if it were never there, the stallion's personality returns mostly to normal leaving a fragment of the "mother's instinct," and Zippity Doo Da, the stallions have their very magical love spawn together.