Lol, kinda depends where you are at in the series.
If you are all caught up, the simplest answer is we don't have a clue. There are plenty of speculations, but nothing is confirmed.
And if this was supposed to be your idea of a rhetorical or sarcastic question, then my bad for ruining it. Lol.
Jerking off to magazines behind some rock.
We dont have a clue. Probably killing some monster. At one period we saw him with Natsu . He will probably return to guild when the war starts.
Gildarts is hardly around in general and when he's away, we don't really know what he's up to. He could be on a mission or just roaming or something. He's bound to show up sometime when the war starts though
Who knows. Probs in the slammer for destroying part of a mountain and making good use of his magazines xD