Yeah, as a kinky asexual myself, it seems like she hasn't been very open in communicating her relationship to kink. Especially when your partner is allosexual, it's so important to explain why you like to participate in kinky activities as an asexual and where your boundaries begin and end.

For allosexual people, sex and kinks have a venn diagram that's basically a circle, and failing to communicate the extent of your interest in kinks as an asexual is just setting the entire relationship up to fail because you're inevitably going to have mismatching expectations from kink play unless you make sure you're both on the same page before you start.

His confusion is completely understandable, as is her identity as a kinky asexual. They just need to talk to each other.