[ Tony does sound happy to see him, and that warms something more than it probably should. It gets a smile on his face, at least. ]

Some kind of transporter technology is my guess, but I haven't been able to pinpoint the tech. And the source is... a little emotional.

[ His smile fades now, though. The answer to this question isn't that exciting. ] Off and on, about five months. I never choose when I leave or when I come back.