Well, as smut goes it's o.k., I think you could use a little work on more graphic descriptions (more research, lol!). The whole adopted brother thing seems like a shallow attempt to differentiate your story from all the other SasuNaru fanfics out there.I suggest you expand your idea. Emphasize Naruto's innocence and inexperience (he was an outcast for a long time, after all) and make the Uchiha clan a bunch of secret, incestuous homosexual perverts. Sasuke could have flashbacks to how his brother initiated him into sex and you could have Itache watching the action secretly (using the Sharingon?) and eventually joining in.