Tuck is telling Winnie how he thought it would be good to live forever. Now he is trying to tell Winnie not to drink the water because he knows the consequences. Some of the consequences are he knows he cant SE the after life and he said to imagine all the Milquetoast would never die they would all bite us.
Jesse is trying to tell Winnie how his wife ran away from him because he wasn't getting older. his wife said it was weird she was getting older but not him. If Winnie got older she would be 10 for the rest of her life and her kids would be older than her.