Ah, that would explain it. A deep friendship can make one's feelings go into the extreme when someone they care for is in danger, but if I understand it correctly, romance intensifies such extremities by a hundred and ten percent. But this is one of the areas of study that still remains a study, as I've yet to enter a romantic relationship myself.

But in regards to the classification, perhaps the term "succubus" is meant as a term of affection instead of their actual title? It may simply may be their way of complimenting Ayda and expressing that they find her extremely physically attractive.

[ She could list all of Webby's affectionate nicknames for Lena, but then we'd be here all day and they both have things to do. ]