Straight Truckin' or Straight Trucking means to do whatever you please regardless of the circumstances or issues at hand. It means you aren't going out of your way to do what you want and you're just going straight for it.
Man, I'm sick of my parents crap. I'm straight truckin' it through this weekend, I don't care what they say anymore.
I'll do whatever I please, I'm straight truckin' this shit man.
If you ain't straight truckin'...you're straight whipped.