I am laaazy so I'm just going to copy and paste from Draco's character information post. I think it mostly all fits, but I bolded the words that were especially pertinent. Draco thinks it's all nonsense, of course.
Gemini is the third sign of the zodiac. Positive traits include quick wits, versatility, flexibility, fluency with words and ideas, an open mind, a love of learning, adaptability, agility, sharp perception, and cheerfulness; negative traits are duplicity, mood swings, flightiness, nervousness, fidgeting, lack of attention span, a tendency to be easily influenced, and undependability.
Ever heard the phrase "snake-tongued?" It must have been invented to describe a Slytherin Gemini. Slytherin Geminis have the dubious gift of being able to lay the blarney on thick, and be believed. This is due to both their imaginative mental agility and to their skill with words. Of course, not all Slytherin Geminis are liars - but it is probably advisable to get all sides of the story if you hear interesting gossip from one of these wizards. Slytherins born under the sign of Gemini are also naturally skilled at any magical work which involves sleight of hand or incantations. They are less determined and aggressive than the average Slytherin, though, save perhaps in a field that involves debate. You will find far more of them chatting in the common room or looking up arcane lore in the library than on the Quidditch field or in a dueling match, with the exception of Quidditch Seekers: the sharp eyesight and quick reflexes associated with Gemini are good traits for a Seeker to have.