What should a nurse instruct the patient to do to ensure a good fit of the appliance to avoid leakage?

Rationale: A. Confirm that the pouch covers the entire abdomen is incorrect because the pouch only needs to cover the stoma and adhere securely to the surrounding skin. Covering the entire abdomen is unnecessary and impractical. B. Place the pouch only when lying down is incorrect because appliance placement is usually best done while standing or sitting to account for natural skin folds and movement, which helps achieve a better seal. C. Confirm that the pouch fits tightly to the edges of the stoma is incorrect because the opening should fit closely but not tightly against the stoma. A pouch that is too tight can cause irritation, pressure, or impaired blood flow to the stoma. D. Check pouch placement to ensure a firm seal is correct because ensuring a secure seal between the skin barrier and the peristomal skin is essential to prevent leakage and protect the skin from irritation and breakdown.