ambiguous_penetration states,
It can also be used in situations in which it's uncertain any form of penetration is occurring at all (e.g. a character is sitting in another character's lap, but it isn't immediately clear that they're having sex). This occurs when the view of the genitals is obstructed either by body parts or objects.
obscured_penetration states,
This will qualify as ambiguous penetration when there is the possibility that the character may have more than one obscured orifice. If the character being penetrated has any of their genitalia visible, or is clearly a male or gynomorph by our gender tagging guidelines, this usually means that penetration is not ambiguous.
In other words, ambiguous_penetration states it can be used for either situations where the penetrated orifice is ambiguous or when it's ambiguous whether penetration is occurring at all, but obscured_penetration states that only the former definition applies to ambiguous_penetration. Which one is correct?