So here's the thing.
I generally don't ship incest ships. Nothing against people who do! It's just that since I don't kink on incest as a kink, and in fact have a few severe squicks involving some common incest dynamics, I don't seek out incest ships specially, and I generally end up shipping unrelated people.
BUT. Occasionally it happens that I do end up shipping an incest ship, and if you're reading this post, it's because I asked for one in an exchange and pointed you in this direction for more info on my squicks.
(Note: If you find my squicks too limiting - perhaps they're exactly the kind of thing you find hot! - please don't worry. I'm also completely happy with sibling-friendship gen. If I'm shipping a sibling couple, I find their relationship attractive, and will like reading about it platonically as well. So if you no longer want to write them romantically because of my squicks, gen is totally great.)
My squicks wrt incest:
* Any incestuous actions, feelings, or even attractions while the younger sibling is under 18.
* The older sibling being the instigator or even the first to be attracted to their sibling. For me to find it hot, it 100% has to be the younger sibling who is attracted first and makes the first move.
* Any hint of power-play related to the familial relationship. (Power dynamics related to relative success in sport, relative hotness/dick size, etc., are all excellent and indeed welcomed. I’m weird.)
* Any noncon or dubcon, including situations/conversations/actions facilitated by alcohol, drugs, etc.
* Anybody else finding out whatsoever.
* Any hard kink with the older sibling as the top (power-dynamic wise - I don’t care either way about top/bottom wrt penetration).
In general I have a strong preference for the younger sibling as the POV character, because it's easier to make their consent, attraction, and agency clear, but it's okay if the older sibling is the POV character as long as those things are still clear.
Meanwhile an assortment of things that are totally fine (not exhaustive):
* Pre-relationship, either sibling being conflicted about being attracted to the other and angsting a lot. Alternatively, established-relationship with little to no angst (if that's your preference).
* Older sibling having to be really persuaded/wooed by the younger sibling, until they’re convinced that they’re not taking advantage of them and the younger sibling really does want this. (I love it if the younger sibling feels the need to prove themselves/earn older's respect in order to be taken seriously in this.)
* Realizations/first times that are facilitated by sporting success (high on adrenalin/excitement/joy), again with the reiteration that it 100% needs to be younger-sibling who makes the first move. (Though not necessarily in that exact moment - if, say, younger-sibling has previously made a move three months ago, and now older-sibling succumbs and kisses them in a fit of exuberance, that’s totally OK.)
* Long-term seduction by younger sibling (starting after age 18).
* Porn, PWP, and porn-with-plot.
Again, sorry that I have squicks! It's complicated when you really like something but also have squicks about it. xD If these squicks are too picky for you, please do feel free to write gen friendship for the selected ship.
Thank youuuuuu. <3