Hebrews 13:4 says "Marriage is honourable in all, and the bed undefiled." That is pretty much saying that married couples can do whatever in their own bedroom as long as it is consenual. However my question is what if a couple who goes by the bible but they are ok with bringing in a 3rd person into the bedroom? I'm not going to get into graphic details so use your imagination. My question is would this be considered a sin? Why or why not?

