Lu Jingchen directly wraps his arms around Song Qiao's waist with an extremely dominant posture, making it clear to all those around that they could guess the relationship between the two!
During the three years she was with Gu Linyuan, because of her naturally calm personality, and considering that Song Qiao herself disliked physical contact with the opposite sex, even to the point of resisting such intimate touches, their relationship had been limited to occasional hand-holding, except for that one time when Gu Linyuan stole a kiss on her cheek when she wasn't paying attention!
So now that Lu Jingchen is holding her waist and trapping her in his embrace, Song Qiao instinctively tries to struggle free!
But as soon as Song Qiao tries to move, Lu Jingchen, seemingly anticipating her struggle, tightens his grip, bringing them even closer!