Looking for a story

[Viros]

I once read a story (I'm pretty sure it was on here) where a guy went his aunt/cousin's house (some kind of relative, not sure), where she put a spell on him and the other girl that was there (possibly another relative), where he began to turn into a girl and the girl began to turn into a boy. Other points of interest are that the spell-casting woman at one point grows a ridiculously huge penis and forces the guy (turning into a girl) to deep throat it. Sadly, I didn't write down the name or bookmark it, and, due to a Windows reinstall, it's been cleared from my history. Can anyone help?