Your boyfriend is going to have to be more specific. After all, what's one man's kink is another man's Saturday afternoon. We all have ideas about what we think is kinky, but it's all judgment. For example, some people think having sex in the living room is pretty wild, while other people would consider this pretty tame. If it's something you wouldn't normally do, or it involves some kind of fetish or elaborate costumes, it could be considered kinky.
Some people also consider things they think of as weird and disgusting as kinky.
But that's probably being judgmental. Just put those type of things in the category of activities that are outside of your boundaries. Because for every person you think of as twisted for some little kink they have, there is someone who thinks the things you do are pretty freaky. I suggest you talk to your boyfriend about this. Actually describing the activities may be enough to satisfy the fantasy.