It isn't a punishment if you enjoy it. If you're talking about funishment, that's different. Also, if you're a "good girl," you wouldn't need a punishment. What's this thread for? If it's for pictures, there are already threads open for that. Like this one.
i may be a good girl most of the time or almost all the time, but i definitely loved when i get my ass spanked whether ive been good or bad sometimes i just need it hahah...
For those who are interested in reading more about spanking, here are links to some prior threads. Note: these links all come from the BDSM Forum Library, which is stickied at the top of the front page. I stopped at 2007 but there are probably twice as many listed in more recent years.