MovieXclusive has it.
Here's the synopsis:
This summer break, the love stories of four distinctive flavors take place all across Thailand in Hormones. Best buddies Phu and Mai will battle it out for the heart of the same girl. Meanwhile, Joe wears sincerity on his sleeves as he decides to put the knowledge of love he learned from books and movies into good use by confessing the crush he has on his university friend, Cee. High-schooler O-lek has a different kind of crush. She has never met him in person but that is not a problem for her to adore a Taiwanese pop-star Ti-Ti. Things are tough for Hern, a boy who has to fight a giant temptation when his girlfriend is away when he meets a sexy Japanese siren aboard a train.
It's a cast of the GTH all-stars, including Charlie Trairat, Michael Sirachuch, Chienthaworn, Ratchu Surajaras, Chutima Theepanat, Focus Jirakul and Chanthavit Sunasewee along with Lu Ting Wei and former AV star Sora Aoi.
(Thanks Logboy, Linus and Kevin!)