doesn't threesome imply 3 people doing it? so to me it is incest, they are participating in the act, just not directly with each other but there are consent there, the mom even help the guy with the daughter several times and like the other guy said there is a scene with the brother and sister playing around.
you know, testicles also participate in sexual intercourse, but they don't go into the pussy, they hang around. capisce?
human relationships are such a broad and deep topic, dude, the world ocean will seem like a small puddle in comparison =)
you can be in an incestuous relationship without having sex, that is, in a platonic romantic union, or two sisters can have sex with a common guy at the same time (threesome) without having incest between each other - one sat on the penis, the other sat on the guy's mouth, both are satisfied, but both are not friends with each other, although they love the same guy.
in the VN "Visit" the mother and aunt of the MC did not have incest between themselves - although they shared their son (nephew), being in the same harem with him. there is two incestous relationships - mom\son and aunt\nephew.
in VN "Banking on Bella" there were two sisters who competed with each other - but I'm sure sooner or later they will have threesomes with the guy they have a rivalry over.
in VN
"Proud Father"we seen threesome with MC, his daughter Rebecca and MC's sis, Samantha. but Rebecca and Samantha was not in romantic relationships, there was no incest of aunt and niece.
in a harem, women can even be at odds with each other, while remaining faithful and tenderly loving their husband. but I'm talking about the eastern harems of rich people, where there were a lot of women and even needed their own internal administration.
options can always be different. but incest in general is a romantic relationship between two blood relatives. although now incest also includes relationships with adopted (STEP-) family members (oh yeah, people love incest so much that for this reason they called incest even what is not incest, *giggle*).
brother and sister from Alice's family - well, this is not incest as such. they are not in a romantic relationship with each other, they have never even kissed. although they may have sex occasionally(fooling around) and as a result there may be an inbred child.
however, in fact (i mean in our current VN) there will be no sex, the brother does not have an erection for women, alas. but maybe if there will be a platonic romantic relationship - then yes then it is incest - incest between a gay brother and sister.
