Shadowheart has a unique stool in her camp that when she's around, she'll react to us sitting on it, and apparently Shadowheart has different reactions too whenever you sit on her stool depending on your relationship with her at that time.
Timestamps:
Bad Relationship 0:00-0:15
Good Relationship 0:16-0:24
Exceptional Relationship 0:25-0:34
Dating 0:35-0:54
Romanced 0:55-1:30