Shredding some gnar is a form of getting girls and eating their pussy.
"Yo dude lets go shred some gnar at the bar"
"Totally dude"
Wicked skate tricks
Straight killin it on a skate board
You guys ready to shred some gnar?
" Oh shit man, Bill is going to throw up some hands"
An indirect way of saying; "I have to shit."
Come on bro, we're gonna be late.
Gimme a minute dude, I gotta snap off some crayons before we go...
The act of engaging or acquiring sex, booty, butt, vagina, yams, or ass from a female.
Or
The act of engaging in or acquiring sex, from your baby or boo or lover or partner.
Jerking in to low quality milf porn
Scott from Canada is always crushing some jerky when his kids go to sleep.
I'll be back in five minutes, I have to go Free some Syrians