Gape on LetMeJizz
Everything builds toward the reveal, a long stretch of hard anal or a thick toy stretching the hole until it stays open on its own after the cock pulls out. The camera holds on that open ring, sometimes pushing in to show how far the muscle has given. Both vaginal and anal versions exist, but the payoff is always that held-open shot.
493 gape videos here, all HD and all free. New ones go up daily, so check back if you don't find your scene first time around.