Careful with
gloryholes! I saw a clip on a site like the OP linked. A hidden camera was based above the wall separating the cock and cock sucker. Guy got his cock hanging out the hole. Lady comes in the room with a guy creeping silently behind. The lady starts talking to the guy with his cock through the hole, and starts to get it hard. Then silently the lady and her partner swap places.
The guy with the lady then gives Mr Gloryhole a BJ till he bursts. Then both leave the room leaving Mr gloryhole none the wiser...