I feel like I've gotten way too desensitised to NTR and it's kinda disappointing.
I remember when I first discovered NTR through hentai OVA's and feeling like absolute shit for a while after. They'd be engraved into my mind though, some mornings i'd wake up thinking about it and i'd have no choice but to watch some just because it would get me so aroused. Despite that, I still felt really bad inside, almost as if it made me depressed. I think that might have been the best part.
Then came visual novels. Oh boy... I don't think I could think properly for the first few weeks. I left classes early just so I could return home. My first VN was Marriage Blue because I really liked the H-OVA. I vaguely recall my heart rate being through the roof playing through that game. Over time that euphoria gradually decreased but there were a few games that would almost return me to initial levels - two in particular were NTRPG2, where I didn't go to sleep that night, and Kabe no Mukou no Tsuma no Koe from Anim, the only two where I don't think i've skipped so much as a single line.
Now though... i wouldn't say it's completely gone, though anything vanilla is still difficult to excite me enough unless its drawn to my liking.
The only other "taboo" fetish that could potentially get me as excited is incest. As far as VN's are concerned though, I can only think of Sister Scheme 2 as the only one I truly enjoyed. VN's spit out incest routes multiple times a month but most of them seem so shit to me. They don't feel like family, and most importantly, they don't spend much time thinking about and acknowledging what they're doing is taboo. In most games, by the second h-scene, sometimes even the first, they're acting like it's something that's completely normal. I've read about cases where people have partaken in incest almost always feel guilt beyond belief and have difficulty coming to terms with how disgusted they are with themselves... Some do it again, others don't. Where's any of that in incest VN's? A well written incest could be more exciting than NTR in my eyes if done right. Don't get me started on character designs either, when you have something like Baku Ane, although a decent nukige VN, absolutely kills any incest vibes with characters that in no way, shape, or form, look related.
Shine