imagine Person A gets night terrors and one night, Person A starts screaming and crying while kicking their legs and holding their stomach. This wakes Person B and gently grab Person A's waist and cuddles up to them. They start whispering soothing things in A's ears, 'shhh'ing and saying 'you're okay, you're okay, I got you.' Etc and somehow, their words get through A's unconscious mind and puts them at ease.