[there's a pause like he's thinking of how to explain.]

The first time I managed to get back was an accident. A portal opened up after we fought Etemon, and I was the only one who got back. Things were starting to get pretty bad and the two worlds were starting to bleed together, so another portal in the real world opened a few hours later. I couldn't leave my friends behind and I couldn't let my partner go back without me, so I went back to that other world.

It was another couple of weeks before all of us got back after that. We were home for a couple of days to save Earth before we had to go back. Usually we go through gates that we find or gates that we open ourselves. [gates and portals are interchangeable in this case.] After we beat Apoclymon and our world and that world started to sync up, another gate opened to send us home. We didn't get to go back for years. Even now we don't always get to go. The timing has to be right or you risk not getting out again for a while.

...the last time I got back a different way, but the others got through another gate, I think. They were already back when I got home.

[like. very recently. this is also a somewhat vague explanation but an attempt was made.]