Horses are like horses, and in a different time (period) and a different place (not a ball), Clarisse gave her a choice between griffons and horses and Hermione picked horses. Unicorns on the other hand...

"I thought these are only friendly towards virgins." That's right, just two smooth-skinned virgins on a unicorn, nothing too scandalous.

"Err, yes - you let me worry about that part and ride." It feels right - though she'll have to hold onto something.