I think of it as a bit complex. Someone fully under hypnosis cannot consent to an act, but I think it should be fine if it's asked before hypnosis is applied and that the situation is explained in details ! I feel like the ability to consent to everything is important, will it be active consent (asking right before the act) or less active consent (for exemple, partners having agreed upon being able to do that sometimes at random and still having the ability to back down on that agreement if wanted)