The reaction Obito was having was evident, especially since Gai was moving around a little in his lap, trying to find a perfect position for kissing him, and Obito wasn't the only getting turned on by the kiss.

He made a low noise and shifted, his hand moving down the front of Obito's robes between them, low onto his stomach. Gai very briefly thought of the ANBU, glad that Neji wasn't on duty at the moment, and wondered if maybe he should stop this here. After all, this was a bit risque for the Hokage's Office, and all they had done was kiss. But that was still improper. Surely. Maybe. As if that mattered anymore, when Obito deepened the kiss like that and Gai could think of nothing but kissing and touching all of his boyfriend.