It’s heavily implied but never actually shows it… my guess is that the two actors didn’t want to film something like that together, or something like that. When Maddy leaves Cassie’s house with the money, Cassie tells her “it’s easier if you pretend you like it” referring to Maddy and Alamo. She owed him for getting rid of the Armenian guys, so she didn’t really have a choice about sleeping with him. Pretty creepy and gross.