What does "crossed up" mean?

Hello everyone, I been riding for about a year & I'm interested in trying the track at one point. I know I'm new to riding but I love to learn & read about riding techniques & whatnot.Anyways, I see people show pics of their body posture, and come across the term "crossed up." I can tell it's something you don't want but what does it mean exactly? via /r/Trackdays https://www.reddit.com/r/Trackdays/comments/8rlmnl/what_does_crossed_up_mean/?utm_source=ifttt