A lot can happen in a couple of seconds…. Especially when you're a time traveler. The Doctor thought he was going to die in "The Wedding of River Song." How did he decide he wasn't going to? Doctor/River
In The Doctor's experience, River had always fit into his arms perfectly. She was always warm and soft and (dare he say) cuddly. However, it turns out, snuggling with a young River Song is comparable to having an agitated porcupine in his bed. Student!River. Older!Doctor. Fairly Fluffy.
River Song gets help from her "psychiatrist" after everything that happened in "The Impossible Astronaut" and "Day of the Moon." No plot. Just fluff.