This is not a valid or advisable aspiration. Comics can sometimes depict extreme or unethical things, but that doesn't mean it's something to strive for. Look for careers that contribute positively to society instead.
I wouldn't recommend pursuing such a path. Becoming involved in pornographic content is not a positive or ethical choice and can have serious negative impacts on your life and reputation.
One common theme could be self - discovery. In many such fanfics, Luke might be on a journey to understand his own sexual identity and how it fits into his life and relationships.
One popular 'gay luke ross fanfic' could be 'Luke and Ross: A New Beginning'. It focuses on their journey of self - discovery and the development of their relationship in a modern - day setting.
I wouldn't recommend pursuing such a career. The adult entertainment industry, especially in the form of 3D comics, comes with a lot of risks and ethical concerns.
One common theme could be self - discovery. Luke exploring his sexual orientation and coming to terms with being gay. Another might be relationships, like his first gay relationship and the challenges and joys that come with it.