Just a few questions regarding what to tag and such (I'm still pretty new to all of this):

If you're tagging a ref/model sheet that's showing the same character but in several poses and such, is it still solo? I imagine it is, but just making sure.

Whenever there's a disembodied penis shown, is it automatically assumed to be male unless specified?

If there's just hands, feet or some other part only shown without any visible body attached, is it ambiguous unless specified?

If a female is performing fellatio, this would count as female_penetrated right? I imagine it would, just making sure.

If there's a conjoined character and only them (let's assume that they've always been like this, born as conjoined), is it solo?

If there's two characters that have been conjoined together, would the aftermath of them being conjoined count as duo or solo?

Most of these are pretty obvious, but I'd just like to verify my assumptions with those who are more adept at this than I.