Person A of your OTP is really embarrased to say ‘I love you’ to person B. So when they are watching a movie together, that person A picked, they cuddle on the couch and eating popcorn. When it comes to a special point, person A is turning his head to person B, which is clearly confused, and turning the volume really loud. Then in the TV, the Girl says to the Boy ‘I love you’ and person A is moving his lips quiet sync. At first person B is pretty confused, before his eyes widend and he replies very loud ‘I love you too!!!’ and hugs person A thightly.