After unlocking the L.30 quest for the Chocobo Companion, I purchased a large stack of the greens and just drag it to my shortcut bar. That'll summon your companion. You may also want to drag the dismiss, behind and the stances if you already allocated points to it. Be warned that I don't believe there is a way to respec your Chocobo companion's points. I made the mistake in dropping a point into each stance and by doing this, there is no way for me to reach max rank in once of the stances. Also just to share, it looks very difficult to raise your rank of your companion. It seems to only get XP from the mobs being killed so it doesn't receive XP from FATEs, quest turn ins, crafting or gathering.
So far the quickest way that I found to level my companion was to chain 5x mobs that were +1/+2 in level to me. If you come across a FATE that has a lot of mobs, you can level it that way to but you need to hit all the mobs and do enough damage to be awarded XP. If you're on a FATE team, the downside is that you need to keep dismissing your companion so you can jump back onto your mount. So you may need a large stack of greens if you keep summoning and then dismissing for FATE runs.
Edited, Sep 5th 2013 7:13am by rubina
Edited, Sep 5th 2013 7:17am by rubina