What it’s about: It’s in the bathroom where we are who we are most. So that’s where Abbi Jacobson and Ilana Glazer start the new season of their much-adored creation “Broad City.” But its toilet humor isn’t cheap. The split-screen montage deftly plunges newcomers into the show’s delirious labyrinth of odd adventures with two BFF chicks who fit nowhere in New York City but together.

“Broad City” brims with free-form riffs and outlandish disasters through which our girls scramble unscathed — oblivious Ilana buoyantly fist-pumping to her own demented drummer, abashed Abbi clumsily testing behaviors in case one fits, together courting calamity like the warehouse sale shirt whose left-on security tag promises impending explosion.

Somehow, that detonation arrives yet more brilliantly bizarre than expected. And we’ve already seen the trapeze act. The traveling porta potty. The 12-pound bike chain fashion statement. Even the speaking subway grate.

My say: Birthed as a webseries by the two veterans of Upright Comedy Brigade (fellow UCBer Amy Poehler is a producer), “Broad City” has blossomed into a certified tube hit. (Seasons 4 and 5 have already been ordered.) Like a packed piñata of absurdity, each episode rains unforeseen treats, from physical pranks to existential banter to all manner of sexual exuberance.

Bottom line: Broad fun.

Grade: A