Japanese by Example
Learning through examples in manga

Filled with carelessness with 〜だらけ

Grammar Explanation: Covered in with 〜だらけ

Manga panel from それでも歩は寄せてくる showing example of Filled with carelessness with 〜だらけ.
それでも歩は寄せてくる » Volume 3 » Page 104

Realizing Urushi is hiding in a box to try and scare him, Ayumu sits with his back to the box.

歩(あゆむ):
「どうですか？油断(ゆだん)だらけのこの背中(せなか)…」
“How is it? This backfilled withcarelessness.”