Imagine that a sloshed, dotty Miami granny broke into a Vegas Showgirl’s dressing room and emerged very pleased with herself. Such is the singular élan of Dame Edna.

Returning again (like a persistent rash) to San Francisco to bring her special brand of good will to all, the star’s lacerating wit and unbridled offensiveness are heinously hilarious. Big, brash and lily-gilded, the Dame Edna experience is a sight to behold and an assault on the sensitive. And, as should be expected for a woman whose fashion sense insists that more is more, Dame Edna clearly doesn’t comprehend the notion that brevity is the soul of wit.

The title of her new show, “Dame Edna: My First Last Tour” hints that this is a gal who intends to milk her routine for every last drop. Here, at The Post Street Theater, stop 3 of her 8 city tour, Edna’s showmanship is on parade for over two hours. One of which, (as the queen of the backhanded compliment herself might say) ,is very good. Mocking and maligning her adoring audience and pummeling us with gladiolas (as par of her signature finale)Edna’s vicious wit and rude barbs are all the more amusing as it is delivered in her sugar-sweet, couldn’t-hurt-a-fly, feigned polite British manner. Oh, yes. It’s also funny because underneath the bedizened frock and the granny-without-a-clue mauve hair, the gaudy glitter and the big eyewear, Dame Edna is actually Barry Humphries, an elderly Australian actor with a wife and kids. Humphries has been doing Edna since 1955. The act has gone from Melbourne to the BBC to Broadway over years. No one can say the show doesn’t have legs -- but maybe the panty hose have seen better days.

Once again, Edna discusses her lifestyle as an absolutely fabulous celebrity hob-nobber. She sings (with Andrew Ross on piano) and shares about her deceased husband’s “prostate murmur.” But mostly she chit chats with her audience in what she often describes as less a show and “more like a lovely conversation between two people, one of whom is a lot more interesting.'’ She interviews audience members for ammunition – and then rips them to shreds. While no doubt excruciatingly mortifying for its victims, the audience participation is hoot for those of us safely out of harm’s way. Edna particularly relishes ridiculing audience members’ personal appearance and age. But she also enjoys making fun of one’s home size and/location, one’s career or simply the selected humiliatee’s hesitancy to answer personal questions. Warning one unlucky participant that she will be soon be called upon to come up on stage, Edna says, “If I were you I’d start tensing up now.” And they do. And yet they submit. On stage, Edna plays matchmaker, bartender, fortune-teller and unsolicited feeder of cheese cubes. During a recent show, however, the Dame was a tad tame. Though her exchanges are Edna’s opportunity to showcase her ad hoc mockery, she retracted her claws with a recent widow, revealing some disillusioning civility. Too often, the rigmarole involved in setting up an audience participation sketch has insufficient pay off. Couches are brought onto the stage, as are wine boxes (both flavors) microphones and bridal headgear. But a cost/benefit analysis is lacking. Even so, an evening of Edna still sparkles with the delightfully bizarre, brazen and gargantuan personality of this barking mad great Dame.