It's very complex because of branching paths. For instance, not only am I on D-only, I have already had D reject Elena. So as long as I'm given the option, no other character other than the MC can corrupt D. Now, what do you think the reaction would be by players who play D-only--the MAIN path after all--to hear D is engaging in sex acts moreso than they are seeing? Yeah, pissed off like you can't believe...
The writing in DMD is so inconsistent, I wouldn't be all that surprised. But really-really : D HAS to be less sexually involved in any other path than she is on the D-only one. When D changed her hair to go on the dinner date with F (where Lucas would sucker punch him), D expressed jealous annoyance at Elena's referencing F. Again, the DMD writing is so inconstant that D's possessive jealousy can be disappeared without a trace. But she is emphatically not into sharing.
Many times in DMD the writers have painted themselves into a corner. Suddenly sprouting wings, they have "escaped". So, even items not expressly on the menu may be brought to a table...