If one picture contains both lesbian and straight sex (not bisexual, but two separate sex acts), what tag should I use? (look e.g. here: post #1860345)

Both since the both of them are present. Though use hetero instead of straight. Keep in mind it does depend on context since that Kill la Kill pic is all separate acts.

So bisexual_(female) and bisexual_(male) should be used only when there is both hetero and homo activity in a single act (meaning that in most cases there would have to be at least three people involved), like in post #1487180? And if the hetero and homo action is in separate acts, like in post #1860345 or post #1807258, then the post should be tagged both hetero and yaoi/yuri instead?

If this is the intended use of these tags, then I think it would be good to make their wikis clearer on this point. I'm willing to do the necessary editing, if everyone is OK with it.

Flopsy said:

So bisexual_(female) and bisexual_(male) should be used only when there is both hetero and homo activity in a single act (meaning that in most cases there would have to be at least three people involved), like in post #1487180? And if the hetero and homo action is in separate acts, like in post #1860345 or post #1807258, then the post should be tagged both hetero and yaoi/yuri instead?

That is my understanding, too. I suppose it can be argued because in your examples, it's the same character with different partners. At least if it is separate characters AND separate acts, there should be no argument whatsoever (like if there's a yuri couple and a hetero couple in the same image, then tagging it bisexual_(female) would be completely wrong).

A logically consistent and TWYS-compliant way to define orientation tags would be to always tag individual behavior, not entire images or acts.

If the image shows:

* a FEMALE or MALE character interacting romantically/sexually:
** ONLY with the OPPOSITE gender -> tag hetero.

* a FEMALE character interacting romantically/sexually:
** ONLY with other FEMALES -> tag yuri.
** with BOTH genders -> tag bisexual_(female).

* a MALE character interacting romantically/sexually:
** ONLY with other MALES -> tag yaoi.
** with BOTH genders -> tag bisexual_(male).

* a FUTA character interacting romantically/sexually:
** with a FEMALE -> tag futa_with_female.
** with a MALE -> tag futa_with_male.
** with another FUTA -> tag futa_with_futa.

These rules would apply individually to each character in the picture. An image of an advanced orgy might have all eight tags apply to it at once. I don't know if this is what people want, though.

Edit: For example, post #1487180 would be tagged hetero (because the boy is only interacting with girls) and bisexual_(female) (because the girls are interacting both with each other and with the boy).

post #1807258 would be tagged hetero (because the girl is only interacting with a boy), yaoi (because one of the boys is only interacting with the other boy) and bisexual_(male) (because one of the boys is interacting both with the girl and with the other boy).

Is this too counterintuitive?

Is this too counterintuitive?

Pretty much the way I would proceed.

Plus, should satisfy blacklisters' needs as well.

Pretty much the way I would proceed.

Plus, should satisfy blacklisters' needs as well.

Yes. In general, mutually exclusive tags reduce expressive power with no clear benefit, unless the old "blacklisting is too difficult" and "makes it harder to find what I want with a two-tag search" complaints are accepted as valid.

I'll also point out that for the vast majority of posts (couples, gangbangs, single-gendered N-somes, etc.), only a single orientation tag would apply and no retagging would be required. What these definitions do is provide a systematic way to handle the more complicated cases that do appear.

So what now?

Just to quickly add my USD $0.02

Flopsy said:

In general, mutually exclusive tags reduce expressive power with no clear benefit, unless the old "blacklisting is too difficult" and "makes it harder to find what I want with a two-tag search" complaints are accepted as valid.

If I'm not mistaken, two or more tags being mutually exclusive simply means that they shouldn't be used to refer to the same thing in any one post, but can be used on the same post if they apply to separate elements in it. For example, the faceless variants and head out of frame are mutually exclusive, but could both be legitimately applied to post #1380977. It'd be similar with the list Flopsy posted.

Well, what now? This image archive lives and dies with properly tagging it's images, so how should we tag??