In this case, they have to work much harder to get their target and in the process, actually fall in love with them. Oftentimes, this may be the result of the person being immune to the charm effects most succubi possess.
Now, take that same being, and throw them into a situation where romantic love comes into play-suddenly they're thrown out of their element and are left scrambling to understand how sheepish and awkward they've become in relation to their mark and they may be unable to use their old tricks on them. And they're often really good at the seduction and sex parts. Feeding, mating, and bonding are reliant on the act, so in terms of intimacy this is all that they know. Often, demons such as succubi, incubi and other creatures associated with Lust have a culture of sex. What do you get when you have a being of pure carnal desire navigate romance without sex? You get this trope.
