Heart-to-heart is a popular online word and gesture, which means to draw a heart with your hand, form the shape of love with your thumb and forefinger, and express friendly meaning to fans or friends.

The gesture of comparing the heart has always been used by idols, because it is easier to compare the heart with your hands than to put your hands on your head when singing. This plus action, plus blinking, constitutes the meaning of the heart. In order to pursue a more lovely feeling, some netizens wrote "Bixin" as "refill" and deliberately misspelled it to show confusion. Later, it was accepted by more netizens, and the "refill" spread. Compared with my heart, it also means that I love you. An expression of love between lovers.