When you have diarrhea so watery and explosive, that when it hits the water, it splashes up and hits your testicles. Usually associated with Mexican, Chinese, or Indian foods.
Oh man, that burrito supreme gave me the worst Niagara Balls last night, I almost clogged the toilet.
by Kerplah July 08, 2013
The unfortunate effect of excessive heat on male genitalia resulting in an insane amount of perspiration in the testicular region.
I was going to go to the carnival last night, but it was so hot out I got niagara balls as soon as i walked outside.
by SuddenlySilly June 01, 2011