English users love to make verbs out of nouns: Impact. Sandbag. Gaslight. And now: teabag. Actually, this one has been around for a while, if not in general usage, since it's a little risque. And that is why it's good to stay current, to keep up with slang. YOu don't have to like it and you don't have to use it, but a little knowledge keeps one from looking like a complete, utter fool. It's not that hard. Just a little research goes a long way. Google. Wikipedia, even.
In this particular case, the irony quotient is just too high to pass up, as it was for Rachel Maddow. It's almost as if there were a mole planted in the Republicans' planning committee. If so, it's the best bit of sabotage I've seen in ages. You can hardly blame her for being on the verge of losing it, with or without the help of her offstage colleagues guffawing in the background. And I must say, this is one of the best use of, ahem, innuendo (no pun intended) that I've ever seen. There's nothing the censors would have found objectionable, but if you understand what the term means in its slang form, the implications are hilarious, and amazingly insulting, considering what a bunch of hypocritical prudes Republicans tend to be. It's genius.