Gladio can hear the others, and he slides his eyes over to Noctis without pulling away. If he had, surely the other would have seen a lewd smirk on his face. Instead his cock is hard and leaking, enjoying the noises everyone was making, but especially the squirming Prompto was doing.

If he was less busy, he would probably invite one of the other two to take care of that for him. For now getting Prompto to hit the peak of his pleasure is top priority, from working him open with the wet heat of his tongue to stroking the man's cock.