This is a learning experience for her. She is now able to understand how the boys in her fantasies feel when being anally penetrated by a huge slab of dong. I'm sure this further understanding and connection will only serve to make her fantasies all the more exciting.
My understanding of it is, and this is merely what I've heard, that fanboys pair up characters for yuri and things simply because it's hot. Or so they say. When a fangirl does it, there's a lot of rationalizing as to why Pine secretly wants Napple, even in official works.
As always, be wary of stereotypes and believing them too much.