It usually features unconventional and sometimes fantastical relationships. The tentacle element adds a unique and often strange dynamic to the romance.
Well, smut manga typically features a lot of sexual imagery and scenarios. Regular manga, on the other hand, can be about anything from superheroes to school life and doesn't focus mainly on sexual themes. The main difference is the emphasis on sexuality in smut manga.
One example could be 'Love Hina'. It has a great story about a young man and his relationships with various female characters in a boarding house. There are some romantic and comical situations that border on the more 'smutty' side at times. The character development and the overall plot of the protagonist trying to find his place and love make it engaging.
The plot itself should be engaging. It can't just be a series of sexual scenes. Take 'Nana' for instance. It has a story about two girls named Nana who are on different paths in life. There are some romantic and passionate relationships in it. The overall plot about their friendship, career aspirations, and love lives holds the story together, and the 'smutty' elements are just part of the bigger picture of the characters' lives.
I recommend the novel "I became the spiritual mentor of a ghost story girl." The main character, Su Ling, was a psychiatrist. The patients she treated were all somewhat strange, including a white-haired loli who could extend her tentacles--Naiyazi. Although the main character wasn't in the form of a tentacle, this novel had a special setting. I hope you like this fairy's recommendation. Muah ~π
In a tentacle monster story, tentacle monsters often have long and flexible tentacles. These tentacles can be used for various things like grabbing objects or moving around. They usually have a large and sometimes grotesque body. Their appearance can be quite intimidating, with strange colors or patterns on their skin. And they may have big, glowing eyes that add to their menacing look.