Well, she had just been teasing, and perhaps he hadn't meant his response to sting like it did, but without James here ...
Lily shook her head and shrugged one shoulder. The rivalry between James and Severus was like the weather. It was something that just was, and answered to no man. "Well." She said, but that was as far as she got before deciding it wasn't worth engaging in. He'd apologized, after all. What was she going to do, anyway? Engage in the same tired, flimsy arguments? James had been a prat, but he'd also grown out of it. He still had the occasional prickish moment and he could be endlessly frustrating at time, and she knew she was at least somewhat biased in defending him.
Just like she'd been biased in defending Severus when James started on about him.
Shaking it off, Lily rolled her shoulders and focused on the glass. Then she narrowed her focus to the water in the glass as she lifted her hand. Pretending she had a wand, she moved her hand in the gesture, emerald eyes narrowing as she ... brilliantly shattered the glass. "Oh fuck," she muttered before she laughed softly. "Suppose I should practice that a bit," she decided.