Quickdraw is done by pulling out the sword or an item just before you hit a body of water and after you get out of the water and press that button the sword/item will appear instantly in hand.
Action Swap is done by doing the same as quickdraw but 2 things will differ, you have to have an item in hand already and you have to get out of the water quickly since Link will put the item away if you stay in water. After doing this correctly, interesting effects happen, such as storing a ground jump and to be able to perform Ocarina Items glitch.
There is a limit of 3 explosives that can be loaded at a time. Explosions (even from an external actor/object) also count toward this limit, but they do not obey the limit themselves. So if you begin to pull a new explosive just before a 3rd explosion appears, it will cancel the draw and you will quick draw the chu. Combine this with an action swap from charged hookshot to chu, and you can store a ground jump (or from having a bottle with content on hand it can let you Ocarina Items as well) Interestingly, chus produce an explosion before they unload completely, meaning you can can reach the limit with only 2 chus (or a bomb and a chu). Bombs actually seem to turn into the explosions they produce, so 2 bombs will not fill the limit when they explode like chus do.
What you do is, have the slingshot/bow/hookshot in hand, backflip into a body of water where you can quickly get out and just before hitting water pull out a bomb/chu and then hold down L button and the slingshot and then press the bomb/chu and you store a ground jump.
Using the explosion limit, you can store a ground jump pretty much anywhere as long as you have at least 2 bombchus.
Same as Ground Jump, you you need to have a bottled content in hand and just before the 2 chus explode pull put a bomb/chu and you'll quickdraw it, giving you the ability to do OI with a bomb/chu