A 33-year-old man presents with a 2-week history of anorectal pain and tenesmus. He reports recent insertive and receptive condomless anal intercourse. He is fully vaccinated against mpox. On the rectal examination, he has tenderness, with 1-2 very painful perianal ulcerations and mild erythema visualized on anoscopy, with some purulence but no bloody discharge. He weighs 73 kg.