Danger, Will Robinson, Danger!
I fell into the trap of telling an ex-SO some of the actual fantasies in my head, without censorship, thinking that she was pretty wild and open-minded.
Turns out, she was right at the limit of her "range", and was thining we were getting too kinky for her tastes. When I opened my mouth, she freaked out! oops. Make darn sure she is receptive, start mild, or toss out a few as a joke first to gauge her reaction would be my advice!