Nice game, and aside from one mistake the level of english is good there was nothing to apologise for.
"his" is third person possessive pronoun for male subjects only.
When talking about female subjects the correct one would be "her".
So it would be "her cunny" for exemple... or her boobs, and his dick.
Although some would argue that gender is based on what's in one's head and not what body parts a person carries nowadays, so it could be considered to not even be a mistake. I don't think so though. Life is about to make do with what you have, the rest is mere delusion. But i digress, sorry about that.
Nice game, keep up the good work.
Although if you plan to tell players the thoughts of other characters than the MC, and to have the player see the girls getting lewd with one another while the MC is away, you probably should remove the "first person" tag - or not, just giving my opinion here.