Jorah Mormont tells Daenerys "They didn't suckle at your breast, they are dragons". In the novel, she did in fact breastfeed her dragons after they hatch in the funeral pyre.
The episode won an Emmy Award for outstanding costumes for a series.
Cersei mentions the "little worm" between Tyrion's legs, to which he remarks that it is not that little. The size of Tyrion's genitalia has been a subject of some debate among fans. In The Wolf and the Lion (2011), Theon inquires with Ros about how Tyrion is "down below", and she responds with "[it] might surprise you". In Unbowed, Unbent, Unbroken (2015), when someone assumes that his genitalia are 'dwarf-sized', Tyrion himself counters with "guess again". There is one passage in the books where George R.R. Martin explicitly describes Tyrion's 'manhood', but nothing to suggest that it is small. In real life, dwarfism generally affects stature but not the size of sex organs.
The episode title refers to Yara's sarcastic remark to her brother Theon: "Why, it's the Prince of Winterfell!". It is also the title of the 37th chapter in the novel "A Dance with Dragons".
Talisa's backstory is a complete invention of the series, as the character doesn't appear in the novels but replaces Jeyne Westerling. Unlike the series, Robb gets injured in the books while attacking the Crag, Jeyne's ancestral home. They grow close when she nurses him back to health, but when Robb learns of Bran and Rickon's supposed death, he is stricken with intense grief, and they make love. Robb marries her not only because he loves her, but also because he feels bound by honor to do so, now that he has taken her maidenhood.