He takes off his shirt, this is the beach duh.
He lays on the sand and wears jeans because denim is superior to bathing suits.
He poses on the wet sand. It's sexual.
He is fed water because he is thirsty and still laying on the sand.
He most likely gets sand in his pants and the director probably shouts "SAVE THE EQUIPMENT."
He goes into the water to rinse the sand out of his nether regions.