1) (Adj) Used to describe anything that has had a negative impact on you, or used to describe something that sucks, makes you mad, or sad. Or, if used in an optimistic way, can be made to sound good or exciting.
2) Used when mediocre words such as suck, awful, bad etc. just can't express how good/bad you feel.
2)"Dude, that rollercoaster was so freaking SHITILICIOUS!!! Let's do it again!"