The subject of this article:
Forrest Gump is awarded the All State Football award for his excellent performance on his high school football team. Forrest had consumed two Slurpees a few hours before he arrived, and was desperately in need of a restroom. After accepting the award, he is confused and does not move from the stage. When asked if he had anything more to say, he said "I got to pee."
This event is specific to the novel, but the film has a similar event in which he is honored on the All-America Team. In the film, it is John F. Kennedy who gives him the award, and who is told "I got to pee."