Lynne is in the bath. George asks her if she posed nude for an art class. He asks her to confirm that she was naked on a couch with a rose between her teeth. He then tells her it wasn't a very good idea. Lynne agrees because the greenfly got everywhere.
Part three of the great art class epic concludes with Lynne having gone to the art class and posed nude. This happens just after the last time Lynne told George about her nudity. George has changed to go out to meet Sammy and Lynne has slipped into a bath. During the time it takes for him to get changed, George has a think about what Lynne has done and has to go back to make sure he hasn't dreamed it.
More information is divulged. It turns out that Lynne was asked to pose on a couch with a rose between her teeth. This is not an art class for amateurs. The artists have already mastered drawing the human form and have now decided to add other objects into their art. Lynne is lucky; if this was a beginner's class she may have had to stand for an hour.
George thinks that Lynne posing nude wasn't a good idea. His reasons are not clear. Perhaps Lynne has some marks on her body from leaning too hard on the wooden arms of the couch. She may have scratched her face from the thorns on the rose. As it turns out, it was because Lynne is covered in dead greenfly that she has been smacking all evening. This explains firstly why she has taken a bath so quickly and also why she immediately took her dress off when she got home. Next week she will forgo the rose.