The phrase appears to be a rather crude and informal expression. A possible translation could be:
The story follows the life of a young man named Tetsuhiro Morinaga, who becomes involved with a gal (a Japanese term for a fashionable and outgoing girl) named Kanaka. The series explores their romantic and erotic relationship, as well as Tetsuhiro's relationships with other girls. The phrase appears to be a rather crude
If you're looking for a specific paper or more academic resources, consider using: The phrase appears to be a rather crude