stupidest shit goin out is used to describe something that is very fucken stupid. this phrase is used alot by tommo. mayoh is always the one who does the stupidest shit goin out, and berkley also does aswell.
Ben: did you see mayoh try and hook in wif dat hot fucken chick?
Tommo: yehhhh.... stupidest shit goin out.....
When someone is utterly bullshitting their way out of something, commonly the failure to attend an event or to give someone something (i.e. gift, debt, etc.)
Bob: Bro, sorry I missed the party, but my girl was all on me last night!
Mike: Dude, your girl was AT the party last night. I can see the shit dribbling out of your mouth, dude.