It's a story about a monk and his chigo/helper, the chigo is blonde. The monk is very respectful and doesn't want to sleep with the helper, but eventually the helper falls in love and begs him to, so they do before the helper graduates. Years later, the monk meets the now adult helper who is an officer (or something) going into battle.
Uke is a 'straight' guy with long black hair works at a beach bar/shop/something. He has a cat. Seme is younger, and a tall blonde surfer.
Have you tried checking the tags yet?
http://www.mangago.me/tag/Surfing/?page=1
I figured it out!: http://www.mangago.me/read-manga/umi_to_futari_no_enbun_noudo/
I like the characters and story in spite of themselves. Who is the seme to be talking about consent when he raped the uke in like the third chapter??