No, Maddie and Percy do not fully hook up and complete a sexual encounter. While they do decide to engage in a sexual act, it is not successfully consummated, and the attempt leads to a definitive end to their relationship.
The Attempted Encounter
When Percy returns to the house, he and Maddie make the mutual decision to have sex. However, their attempt is interrupted before it can be completed. Percy ends up ejaculating on Maddie's thigh before he can even achieve penetration.
The Aftermath and Resolution
Immediately following this unsuccessful attempt, Percy reveals that he is aware of all the circumstances regarding Maddie. He then explicitly states that he does not want to see Maddie anymore, signaling a final break in their connection. He further adds that she will end up living in Montauk for the rest of her life, emphasizing the conclusive nature of their parting.
