Some observations (take them or leave them) on this thread.

You're obviously very excited about pursuing this idea. It's not surprising you already have specific, creative ideas about how to execute this, such as not being able to get hard for an effect of realism. If you feel this strongly about it, creativity can lead to incredible things, not to mention attracting a following of like-minded consumers who may really respond to your ideas. Including people who had no idea they'd find this erotic.

On the other hand, this content raises red flags all from the get go. You never know, maybe it'd be smooth sailing, especially at first. Ultimately, the serious risks already described by more experienced webmasters than I really can't be ignored. To be honest, it seems not only terribly risky and possibly dangerous business-wise, but also to the models.

Seems what it boils down to is if anyone is being hurt, and how and who is ultimately going to have the power to define this.

Personally, I wouldn't go near it period. Of course, it is completely your call.