Put it at the cut where the wait ends and the next scene begins, after the waiting footage has played out. Follow it with the SpongeBob Sad Song when the delay turns into disappointment, or open with the You What SpongeBob Sound when a character first notices how long things are taking.
Sobre este som
This is the Spanish narrator line announcing that one eternity has passed, delivered in a slow, grand, deadpan tone over about two and a half seconds. It feels absurdly dramatic for an ordinary delay, turning a small wait into something epic and making the listener laugh at the exaggeration. It comes from the Spanish dub of SpongeBob SquarePants, where time cards mark huge jumps between scenes.