"Gaped Asshole" is a term used in adult content to describe a specific type of anal sex scene. In this scene, the performer's anus is stretched open or "gaped," often times by a sizable object like a dildo, finger, or penis. This allows for visibility and focus on the sphincter muscle. It can also refer to scenes where the ass is spread wide apart, even without penetration. The purpose of this scene could be to showcase a extreme level of anal penetration, kink or fetish, or simply to show the extent that one's asshole can be stretched open.
It may not specifically be in English, but the term "gaped asshole" is widely understood among adult content viewers and creators who speak English