Need Help With An Artistic Decision. (Patreon)

So I ran into a little issue with this Daybreaker x Nightmare thing while working on it. In this "story" Daybreaker will impregnate her sister, but to do that she has to magic herself a nice, fat, futa cock and balls, but I am having an issue about how I should display this...

My question to you guys is, how should I display Daybreakers stallion junk in the comic? Should she change her gender all together to be a stallion, or should she keep her pussy and just grow a dick and ballz under her mare bits?