I can't help but think that those who think their wives are cool with this (or will be cool with this) might be mistaking a wives capacity to try something new or tolerate something FOR HER HUSBAND with being into it.
To anyone thinking of taking this into the bedroom, talk to your wife first and with total honesty about what you are thinking. You can't sneak this in. That is the only way you will know she actually cool with it and not being kind.