She can still stress basic, common-sense things, like the importance of good communication.
Kumi's independently invented sadism and masochism, so Ishaza's able to give her her words for those two things once she develops the ideas more. Bondage and discipline are harder to derive; Kumi seems to think they're all one thing, which in a sense they are. Kumi settles for calling them both "Restriction", and they move on from there using that as a stand-in. It's not actually important to rederive exactly BDSM.
Consent is hard to express as a unique concept separate from basic common-sense knowledge, especially when she can't mark it as important by giving it its own word or specifically discussing agreeing to things beforehand. It's like watching Kumi trying to discover the concept of human rights from a bunch of court rulings. It's not trivial, even with Ishaza nudging her in roughly the right direction.
In a real sense, Ishaza is playing a very old subgame here. There's a whole set of rules about what summoned representatives can and can't say about technology to prevent every iteration of the game being played from immediately devolving into the most advanced world in all pharasma's creation. Gozreh would mutiny - that's giving the game to Abadar - but Abadar and the other gods nonetheless want to be able to inspire inventions. However, no god wants every god to be able to send a dozen innovations that build their strategy. What an individual deity's representative can do is thus subject to a game of implication and insinuation from ostensibly general advice. The more the mortals have to work for it, the more can be transmitted... but it's a laborious process, and slow.
Eventually Kumi has to go sleep. Ishaza doesn't need to, so instead she talks to Shelyn's church.