Ah, the age-old tale of begging for nudes. As creative as you think you can be, keep in mind that most females have heard it all.
My advice would be to quit while you’re ahead. If she’s taking the time to text you, ride that wave and play nicely. There will come a time when trading nudes are second nature, but I can assure you if you’re asking for them, it’s not the time. You’ll just get put through the ringer like this guy.