Circles

Question
i got a new female rex yesterday. Atfirst shed honk loudly anytime i went near her, i started petting her and now everytime i put my hand in the cage she stands up on her hind legs nips me and then runs in circles around my hand. What could this be and could it be because i have a male rabbit caged next to her?

Answer
If either rabbit is intact, this behavior could indeed be related to sexual hormones having turned on.  Circling and honking is usually associated with sexual behavior.  

Now the other possibility is that because she's new, she's feeling a little aggressive or territorial.  She may need some time to adjust to her new surroundings.

But honestly, this behavior can be considered classic rabbit behavior for a rabbit that is sexually active and feeling the need to mate.  If you don't want this behavior, you'll want to have her spayed and if not already, the male neutered.  It'll be better for their longterm health, and it makes it easier for them to be friends if that is your intention.