Anything that turns you on and gives you sexual pleasure can be considered a fetish, although the technical definition links a fetish to an inanimate object. Body parts can be considered fetish subjects. We would say that CBT is more of a kink, which is a sexual activity that falls outside of “acceptable” sex as defined by traditional society.
However you like to label it, CBT is incredibly popular and enjoyed by many. Including you, if you play your cards right…