This phrase can be broken up into two parts. "Tax That Ass" is to have sex with a female in a manner that depletes the energy of the female; in a sense, "taxing" her stamina. The second part, "Like Woah," emphasizes the taxing of the ass.
Popularized by the channel 'Oversimplified', there phrase refers to the over-taxing of the 13 colonies by the Townshend acts, nearly taxing every single good.
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.