Meaning:
“比” is short for “比划” (bǐhuà, meaning “to gesture”), and “心” refers to “heart.” This term is used by Chinese netizens to refer to the lovely gestures of making the shape of a heart using one’s fingers, hands or arms to express love and friendliness. The heart gestures have been especially popular during the Tokyo 2020 Olympics as many athletes, coaches and even the IOC President Thomas Bach made the gestures during the Games. Traditionally, one can put both arms on top of their heads to make a big heart gesture, or put both hands into a heart shape above their waist. The Korean heart, or finger heart, uses one hand by crossing the thumb with the index finger and has been popularized by K-Pop singers. Here, the hand is about the size of a human heart, while the V-shaped index and thumb fingers represent the two valves of the heart.
Example:
A: 这一届奥运会好多运动员在领奖台上比心。
Zhèyījiè àoyùnhuì hǎoduō yùndòngyuán zài lǐngjiǎngtái shàng bǐxīn。
Many athletes made the love gestures while receiving their medals on the podium.
B: 是的，运动员们传递了积极友爱的正能量。
Shì de，yùndòngyuánmen chuándì le jījí yǒuài de zhèngnéngliàng。
Indeed, they are spreading the positive message of love and friendliness.