If there is only going to be one final set of kiss scenes, then something neutral that allows for different interpretations is the best solution.
I see what you mean. I can't agree with you. If the player clicks on something intimate like kissing or hugging, clicks on it themselves, that is bringing the character to it, and it's the character's "let's kiss?" line.
Choosing fear or pleasure as a reaction to something intimate when you could break up at any moment causing some confusion that shouldn't be there when it comes to a story in which consent is implied.
People perceive neutral faces differently, on different facial structures. Sometimes they think it's sad, but it's just a relaxed face.
Neutral faces can be perceived cold as ice, the player will feel that "something is off, it's the kisses, what's up?" that the character is asking for.
