The last thing Gladio is going to mind at this point is John's scent on him. With his scent on John, this Guide is his and he'll be damn proud to show it off in either way. He knows he's scented Noct on Prompto before plenty of times and the other way around a few, which if he hadn't been around Noct since the time they were young might have driven him into absolute insanity a few times. It still sometimes had come nearly to blows even though he knew the Guide was claimed.

Here... they're going to have an issue. Gladio's as dedicated and determined as a lover as John is, so the 'who comes first' ought to be an interesting sexual 'debate'. As it is, Gladio does back off on John's request. Really, he's not entirely blind to reality. John's got some years on him, won't recover as quickly. He's still young (too young, according to John) and can.

He pulls his hand away, a smirk coming to his lips as he looks down on his Guide. "Maybe I'm not against the idea of having you wrung out and pliant under me, you know."