How could she do this?

My new girl friend and i have been together for about 6 month, I have known she was a cheer leader, and did some dance growing up. So i knew she was strong and flexible, but the other night i walked in on her...orally gratifying her self...HOW COULD SHE DO THIS??!! is there any way for me to get flexible enough to do this for my self, I admit, I felt jealous, but once I can Ill show her, and tips are welcome.