Being composed of something that is "awesome (awesomesauce), true(trufax), in need of more (desu and cowbell)" it is mainly used to describe something good that you want more of.
Wow! That ice cream was awesomesaucetrufaxdesucowbell!
adj: Take awesome, multiply it by the power of awesomesauce, then multiply it by the sheer awesome of a thousand ninjas, and you will have something that is pretty close to being awesomesaucetastic.
"Dude, did you see that guy? He just somersaulted off a 20 story building, fell 170 feet, snagged a kitten out of a tree, landed on his feet, stopped that guy from stealing candy from a baby, discovered the cure for cancer, and established world peace!"
AW-sum-sauce-i-kal. Another form of awesomesauce. Used in situations when the ever so awesomesauce word, awesomesauce, will not fit into the conversation.
Awesomesaucical: referring to the amount of awesome contained in a specific object, person, or event. Mainly created just to have a few extra syllables of gibberish to say. However, awesomesauce may be used interchangeably with awesomesaucical as an outburst.
(Note: Unless awesomesauce is actually invented in the near future ({as in sold in supermarkets, which I would totally buy}) nothing can BE awesomesauce, and awesomesauce cannot be in your possession, or in your power. Therefore, you may only be awesomesaucical. Not awesomesauce.)