Place it immediately after a refusal in your edit, then follow it with the sad violin for an exaggerated defeat, or let Nelson's ha-ha answer it when the refusal is meant as a joke. Keep it as the reaction beat, not the opening, so the plea lands after the decision is clear.
Über diesen Sound
This short clip is a single drawn-out whine, 'But Moooooooom,' stretched over about two seconds in a high, pleading child's voice. It sounds like the exact moment a request has just been refused and one more complaint is coming anyway. The tone is funny and exasperated rather than angry, turning a small denial into an over-the-top, instantly recognisable plea.