Also, you can make erotic scenes w/o explicit sex/porn. Out of many ideas, general idea about eroticism (comparing to p0rn) is to leave much for imagination. Two [edit: three] examples:
1. Non-standard camera angle. For example MC voyeurs Angelica when she is in closet/bathroom other place with "suspicious (of screwing her)" male. MC tries to look via keyhole. And 100% adult games allow that. But not this time. Keyhole is useless for some reason, BUT! Door have holes in the bottom, so MC voyeurs there. And he see, like I said, erotic, non standard thing with much left for imagination. Two pairs of legs, Angelicas to the left facing to the left, and males to the right also facing to the left. He has his pants down. So player KNOWS and IMAGINES sex between them.
2. Second idea is when Angelicas said that she be in place X. MC goes near place X and hears lovemaking and/or see that suspicious male leaves this place. You can add, for disinformation, non-cheating explanation. MC and player wonders if she had sex or not.
3. Oh, I almost forgot brilliant ide from JAP games. This is ... parametrization. SOMEHOW MC, or just player, could see Angelicas statistics. Most important is "first sexual partner" and virginity status. Many JAP games use following virginity solution - female can loose it, player can load save and loose it (for her) later. Also, "First sexual partner" has some psychological impact. Because every time player see that stat, some feelings start just by seeing this stat. Other parameter, very popular, is location. For exampel player has info (somehow, magic maybe?) that Angelics, at 02:00 AM is in suspicious male apartament. And that is all! Player already impiles sex, but is unsure.