Oh, I love the way you chose to tell this -- not only because I'm a sucker for the outsider POV, but also because Ivo's such a wonderful character. I love his observations and his perceptiveness.
"And Severus and Minerva?" she prompted.
Ivo rolled his eyes, but only in his mind. To him, they would never be "Severus" and "Minerva," no matter what he had seen them do. "Professors Snape and McGonagall," he said.
Yes! (But at least she didn't refer to them as 'Snape and Minerva', which would be... Ugh. Sexist, much?)
Coming to think of it, Miss Morris sounds a little bit like an RPF shipper.
In answer, McGonagall moved to him and kissed him hard. "A very great idiot indeed," she whispered. "And so are you."
*sighs* This whole passage is so romantic, and the sex scene is gorgeous.