The Way, Way Back (film)
From BoyWiki
Duncan is a cute but akward 14 year-old at a beach vaction town for the summer with his mom and her awful new boyfriend. He is angry and depressed until he meets Owen a 30-something guy who owns a waterslide park. Owen offers Duncan a job and mentors him, helping him develop self-confidence and happiness.
The film ends with one of the best crypto boysex metaphores ever!