Is it normal my girlfriend dresses up as the cowardly lion from wizard of oz?

It started last Halloween when she dressed up as the Cowardly Lion and I was the Scarecrow. It was an interesting role play. She was never cuter to me than when she was pretending to be a character, it brought out a certain innocence, vulnerability, and desire for affection that attracted me. It brought out her caring and gentle nature as well.

Ever since then we have tried to repeat this experience a few times. I decided to switch it up and cross dress as Dorothy, it turns me on so much. It always starts out as being completely non-sexual in nature, with her coming close to my face and acting all cute and flirtatious and scared, and I always have to restrain myself from kissing her. She always asks me what Kansas is like, what happened to my dog Toto, admires my ruby slippers, tells me to hide from the Wicked Witch, and asks me what my wish will be when I finally reach Oz.

I answer that my wish will be to get back to Kansas to be reunited with my family, but not before having sex with the Cowardly Lion first. It's a weird kind of gender reversal fantasy role play but it works for me. So I let her show me the strap-on she was hiding from me this whole time and peg me as hard as possible up the rear end. Then I reveal my secret that Dorothy is a transvestite and I take my turn dominating the Cowardly Lion.

EDIT: this video is as close I could find to what I'm describing :)
http://www.youtube.com/watch?v=QJlUk0iHu4Y