Sizhui bites his lower lip to keep from outright grinning, but the left side of his face quirks faintly anyway with the knowledge that he's just laid out a huge trump card. He darts his attention toward Jiang Cheng's hands, watches them grip tighter then tilts his gaze back up, heartbeat skipping at the sound of his breath catching like that.

“Do you like them?” he asks breathily, resettling the waistband low on his hips. “I thought you might, that's part of why I bought them.” Holding steady with one hand, the other dips between his thighs, palming his cock through the lacework, deliberate in avoiding the head like he'd been told. “Mmhmm,” comes the slow drawl, the hand stabilizing him on the desk reaching to lift his shirt and tuck it underneath his chin so Jiang Cheng can get a better view. “You make me so wet, professor Jiang... it's a wonder I get anything done after I see you on campus.”