Screaming Orgasm is a drink served in certain up-to-the-moment bars in Ankh-Morpork, as frequented by off-duty coppers such as Angua, Sally and Cheery. It consists of Almonte, Wahlulu, Bearhuggers Whiskey Cream and vodka. It is first mentioned in Thud!
On Roundworld, this cocktail consists of 2cl vodka, 2cl coffee liqueur, 2cl Amaretto, and 2cl Irish Cream. One assumes that Almonte is analogous to Amaretto, and that Wahlulu is coffee liqueur [cf. Kahlua, a prominent Roundworld brand]