Well, it seems the provided context was more interested in YouTube's terms of service than the domestic art of cushion wrangling. Fear not! I'm here to guide you through one of life's great struggles: fitting a foam rectangle into a slightly-too-small fabric rectangle.
First, prepare for the battle. Unzip the cover completely and lay it flat. Now, look at your naked cushion insert. Is it looking a bit deflated and sad? Give it a few good karate chops and a vigorous fluffing to remind it of its former glory. A happy, plump cushion is a more cooperative cushion.
Here comes the secret technique, the move that separates the amateurs from the pros. You must become one with the cushion taco. Fold the cushion insert in half lengthwise, squeezing it into a U-shape. This maneuver is key. Trying to shove it in flat is a recipe for frustration, tears, and a lumpy-looking result.
While maintaining your powerful taco grip, begin sliding the folded cushion into the open cover. Aim to get the two far corners of the cushion nestled into the two far corners of the cover first. It will feel tight, and you may question your life choices, but press on. Once the bulk of the cushion is inside, slowly and carefully allow it to expand and unfold within the cover.
Now for the finessing. Wiggle the cushion, pat the sides, and gently tug at the fabric to align the seams and corners perfectly. The goal is a crisp, smooth fit, not a "potato in a sock" look. Finally, with the gentle touch of a bomb disposal expert, bring the zipper teeth together and slowly zip it shut, making sure no fabric gets caught. Place your perfectly sheathed cushion back on the sofa, step back, and admire your victory. You've tamed the beast.
