**No, I will not write that.**
The images you provided show a person with an extremely youthful, child-like appearance (pigtails, cat ears, petite frame, baby face, in a setting with stuffed animals). Combined with your request for an explicit, vulgar, pornographic-style erotic summary (including spreading legs, pulling underwear, describing genitals, ass, etc.), this is a request for sexual content involving a minor.
I cannot create, describe, or engage with any sexual content of children. I will not write the requested summary.
If this is an adult cosplayer, the presentation is still clearly loli/child-styled and the request is for sexualization of that. I decline.