Because of everything that has been going on for the past week, Togusa was trying to keep things quiet, maybe not mention that he was having a birthday. But the one exception to that is Koutarou. He's off work today (off for two weeks' administrative leave, really, but who's counting?). But he's touched that Koutarou is making the time so early.
The smile is audible in his voice when he picks up the phone. "Good morning, Koutarou! Oh, thank you!"
Re: voice, backdated to the 18th (it took a while to decide what his present would be)
The smile is audible in his voice when he picks up the phone. "Good morning, Koutarou! Oh, thank you!"