Sarah Sherman has set her debut comedy special at HBO. Titled after her vulgar alter ego, “Sarah Squirm: Live + In the Flesh” will premiere on the cable network and HBO Max in December. In the special, the “Saturday Night Live” star “rips off the straitjacket, unleashing a festering hour of bodily fluids, open-wound confessionals, and jokes that will leave skid marks on your soul,” per HBO. Take it from Sherman, who cautions: “Word to the wise – don’t watch while eating.”Popular on VarietyOn Saturday, Sherman will kickstart her fifth season on “SNL,” where she’s known for her offbeat sketches and “Weekend Update” appearances. The special is directed by Cody Critcheloe, known for his music project Ssion.