1)a combintation of the two words Shits and Giggles,
which means just for fun and no purpose. used to help explain why you did a ceratin thing, when you honestly dont know why you would ever do that to begin with.
2)A nickname/ slang term for a person who does random things for no apparently reason all the time. not necessarily a bad thing, but sometimes can have the connotation of a clutz or girl who does the most random crap you can think of.
1) Jon: dude, want to start a band?
Josh: sure, but neither of us have musical talent or time...
Jon: yeah, we can just do it for fun though
Josh:yeah, just for shiggles
2) Adam: dara, why on earth would you put your hampster in a microwave?!?
Dara: idk... XD
Adam: *sigh* ur such a shiggles.