Deuce Juice is the toilet water that splashes up and hits you after a large forceful crap. Some also refer to their very watery diarrhea as deuce juice - think shit piss.
Walker started to spit uncontrollably after he dropped a monster grumpy and the deuce juice splashed up between his legs and hit his lips.
Definition:
The unholy moisture that collects between your butt cheeks after sitting too long, sweating too much, or just existing in Satan’s armpit-level heat.