I feel like Rookie!Leon would be fine with being submissive, but would actually be embarrassed to try and be the Dom. Like he wants to, he really wants to, but people call him "cute" and "soft" and "babyface" so often he has a hard time believing he won't just get laughed at if he tries to come off as domineering. Maybe you even have some doubts about keeping a straight face, but when he musters up the confidence to ask you to try he turns into a completely different person.
He loved servicing you as a submissive, but getting to hold you down and force the pleasure on you was addicting. Leon still enjoys both, no matter the era I think he's a switch, but there was a good few months after that first time where he was trying every dirty thing he ever thought about doing to you when he got control in the bedroom.