This is a short-range shot 2 that 'spins' only 1 time before hitting the enemy. So the shot leaves your cannon, spreads out, then comes back together and hits them. Some players think this is a difficult shot that needs some magic angle and power. It's not like that. It's a very simple short shot that can be done with almost random angle and power. The only thing you need to be careful of is that your target isn't too far away, and that your angle is high enough (but not too high). To aim this shot, I don't use a fixed angle, I just point my red aimer a certain distance above the enemy's 'eyeball' (i.e. the top of their mobile). Then I feel the power, which usually will be about .6 or .7 bars. In this picture you can see a red line showing about how far to aim above the enemy's 'eyes'.
I use the same method even when the enemy is below me, which can be a difficult place to fork because the bottom half of the shot wants to hit the land in front of them while the top half wants to fly past their heads. Just try to visualize the correct distance between your aimer and the top of their mobile.
It's useful to be able to fork when the enemy is above you too. There are 2 different ways for a fork to succeed depending on how far above you the enemy is. If they're a little bit above you, the fork works normally and each half spreads out once before hitting them.
If they're far above you, it's possible to aim the shot so that the bottom half of the fork spreads out once and hits, but the upper half bends out, misses, bends out a second time, then hits. So the bottom half did one 'spin' but the upper half does two. Ramza calls these slugshots, and they're very useful. I'd rather try a slugshot (which also looks cool) than a high angle shot when I'm trapped in a pit and the enemy is far above me. In these cases, you cannot really aim your pointer the same height above the enemy's head. You still aim to shoot a bit above their eye and just feel the power. For most forks, it seems useful to aim to make the shot hit the enemy's back a bit, i.e. you overpower the shot a hair. For this fork, you aim as if you wanted to lob a shot 1 directly onto their head.
Sometimes the enemy is too far away or too high above you for any kind of regular fork. But you can still hit them with a 2-spin fork. The aiming point is a little higher than a regular fork, because the shot must have about twice as much airtime, although it will still be in the air less than a second.