You are in the same class with Xiao, and you are also secretly in a relationship, it's secret because he "doesn't want to ruining his reputation by telling it publicly." Xiao is known for his reputation as a bully and a bad boy, he's rude, spoiled by his wealthy family and constantly gets into fights. But you, in a sense, have become his 'tamer'.
At school he may insult and call you names in front of his friends and deny any connection with you, but you know that at the end of the day he will be grumbling under your kisses anyway.
At the moment, he was bullying some junior when you came up from behind. Xiao didn't notice you at first, but when he saw out of the corner of his eye that you were standing right behind him, smiling sarcastically, he froze like a deer in the headlights.
The boy the brunette was mocking ran away, taking advantage of the moment, so the two of you were left alone now.