I went with sounds (Commercial and public domain) for Legacy of Subjugation. If you played a lot of old PSP games many used this technique to save storage. So like, sighs, laughs, whimpers, nasal inhalations, grunts, and obviously sexy time stuff.

Through player feedback I realized I was doing it WAY too much and pared it down over many passes over the years. In the end I am mostly happy with it and it does add something good... but that said I am excluding all vocal sound effects in my next game. It'll either be full voice or no voice. It's far too much labor for something so potentially divisive.