This seems like something that would be really fun, interesting, artistic, creative, adventurous and new. There is a minefield of issues, however.
Where does one find a model? Location? Time? Starting off? How to maintain sexuality without sexualizing the situation? Staying somewhat professional, that is. If you’re male, how do you come across as not being a creepy pervert?
It seems like a catch-22, how do build a portfolio without a portfolio?
Edit: and then there’s the reaction of your partner. I guess it is much like an actor kissing somebody else on stage.