As everyone knows, if two people punch at the same time and their fists collide, the force absorbed by the one with less strength from the one with more strength will be significantly greater than the force absorbed by the one with more strength.
Simply put, the one with less strength will definitely feel more pain. Since fists are not walls and cannot reflect all the force back, according to this logic, when Song Yun punches Lei Chenyu, and Lei Chenyu is the weaker one, he cannot fully counteract Song Yun's strength. The remaining force will inevitably be directed towards Lei Chenyu. This is common physics knowledge, something even someone like Song Yun, who didn't study much, understands. However, at this very moment, Song Yun clearly feels that the force which should have been directed towards Lei Chenyu has somehow actually rebounded back onto his own hand.
