While it wasn't the circumstance he was preparing for, Tony gladly steadied the cup with his freed hand, a small price to pay for still being able to fluster Jon by flirting. Jon's smirk that looked more like a grimace broke what control Tony had over his chuckle, so it was at odds with the serious frown he tried to knit his brow into and his thoughtful nod as he gingerly took the cup from Jon for now and coaxed him off of the desk with the hand brushing up his side. "That depends," Tony purred, and drew back into his casual seat again with an inviting tug to Jon's shirt, "on what you're willing to do to get the grade."