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.
With neutral I meant something like a smile or look that would seem normal for someone to express when someone they are in a relationship kisses them.
If I want to roleplay this as a relationship where Tav is controlled and treated as a possession I can still imagine things such as forced smiles or putting on an act. It's easier to imagine Tav acting like they are enjoying it when they aren't, than to imagine Tav acting like they are scared when they aren't.