The same concept as prarie dogging and having a turtle head poking out, just combined into one phrase. A chance to drop both bombs at once.
'For breakfast I ate a kale salad, a bag of baby carrots, a can of beets and a ginger apple smoothie. I just drank a strong coffee, took a bump of coke and a drag of a cigarette and now I'm turtle dogging the most epic schwoop poop ever.'