Updated Illustrious XL version.
Since Illustrious XL is not aware of foreskin, "foreskin" tag doesn't work at Illustrious version.
If you don't want motion lines, you may add "motion lines" and "shaking" at negative prompt.
Seems to work along well with penis size slider .

Illustrious XL版をアップデートしました。
Illustrious XLは包茎ちんぽをあんま知らないようで、"foreskin"がまともに機能しません。
motion linesが勝手に描かれる傾向がありますので、negativeに"motion lines"や"shaking"を入れたらいいかも？
Penis size slider と併用可能です。

Civit Link: https://civitai.com/models/430102/pony-illustrious-xl-cross-section-for-small-penis