You'd probably need to rebalance how affection is gained as a whole. There's no "hint" on how the mechanic even work, relying intuition can fail flat as it's basically the player guessing what you think, which isn't as obvious as you'd intend it to be. It's hard to strike a balance between not literally holding the player's hand, but also not leaving it too ambiguous such that the player ends up thinking/expecting a vastly different outcome than one you intended, and imo the game is leaning a bit too much into the latter.That's what I mean. If that amount of grinding would result in having sex and all the between steps like bathing, touching, mutual masturbation, giving and receiving head, and so on, would that strike you as a good balance? ^_^
-6 should be very salvageable!
From personal experience playing it for a few hours before throwing in the towel, a lot of things I learnt are trial and error. Intuition helps a little bit, but a lot of things does not seem to work the way I thought it would. It's also hard to say if that's mis-matching intuition, or if it's a bug (seems like imouto is doing the chore every day when she got home, which is either a bug or confusing mechanics, given that you're given a chore timer implying that not everything needs to be done daily). Affection falls too easily without the game letting you know exactly what's causing it, while the player are locked out of what I'd assume to be most of affection-raising options, which are gated from having some affection to begin with.
Pair that with the massive amount of interaction option without any real depth at the moment, it's hard to say if you're playing properly. There's a massive amount of dialog options, which doesn't seem to do much. As a suggestion, what you could do, is having big topic categories, with gameplay/interactions slowly expanding on sub-topic as a minigame, which would massively reduce the amount of option thrown at the player at the start of the game, while maintaining your overall conversation topics. For lewd topic, this also provides a nice progression from one topic to the next, without having the player guessing when it's finally appropriate to move to the next one.