While in high school, I always had a fantasy about spanking a cheerleader (their short skirts turned me on), or girl volleyball players (loved those tight uniforms), and especially my GF. But opportunities never presented themselves until we came back to her place after an 18th birthday party at her uncle's residence. It was a family deal and her parents stayed, saying they wanted to play cards and talk with other relatives.
Back at her house, we started watching TV and I said "You know, you didn't get a BD spanking."
"so what," she said, in a daring tone of voice, almost like a challenge.
I playfully grabbed her by the shoulders, pulled her over my lap (she offered no resistence), and began to spank her playfully, to which she said, "I had better BD spankings as a 10-year-old."
"I guess I'll just have to lift your skirt," I said, to which she responded, "You woldn't dare" to which I did, only to discover she was not wearing panties. She laughed when I asked her if she was that way all evening. She said she wasn't, but she did remove her underwear just before she left her uncle's place, just in case we went to park somewhere.
Her firm butt was too tempting, I started over, turning her cheeks a crimson and making her wiggle with pleasure (I think)before I got to a dozen, and finished off the treat with a 19th spank for "many more birthdays like this."
As she sat on my lap after, she said she had wanted a birthday spanking, just to see how it felt ... and she said she had enjoyed it, although it stung quite a bit.
I don't know who got more pleasure, she from wanting a spanking, or me, who had wanted to give her (or any girl) a spanking. The bare butt was a bonus.
Through the course of the summer, I could count on one hand the number of times she wore underwear when we went out regardless if she was wearing a knee-length skirt or tennis shorts.