Doggy love?

I have a chihuahua and she seems to have an unhealthy obsession for mounting my arm. yes she is a girl but she loves to clamber on. any ideas to dissolve this hobby my pooch seems so fond of? having her spayed is not an option coz she is tiny and it is risky, setting her up on a blind date is also not an option coz again she is small to carry pups!
Answer
Tap her on the head lightly and say no and place her on the floorit may get annoying at first but after a while it will soon sink in!