There were no words to described the look Severus gave Lily other than "go to hell". He managed not to say it, but it was difficult. What he didn't stop himself from saying, however, was, "And maybe Potter grows a brain between now and then." He winced as soon as he said it, realizing that without James there, bringing him up made him more of a sore subject than usual.
"Sorry," he mumbled quickly and quietly. He wasn't good at apologizing and never had been; the only person to ever get an apology from him had been Lily.
He nodded slowly. "Wordless and wandless. You can do whatever you want. This is the Lily Evans show." It always has been. Really, there wasn't much Severus could teach her. Everyone's technique and aptitude was different, but he was willing to sit by and encourage her, if he got to pretend for a moment that she still liked him.