I agree, it was great that your husband brought this to your attention. If you're uncomfortable with your husband talking about certain things then you need to set the boundries of what you consider okay to talk about and what isn't. If your husband had sense enough to tell you that he did this, then he has sense enough to respect your boundries. And I don't think that your husband had that much disrepect to tell his friend, " Spank her ass and tell her she's a dirt girl. MY WIFE LOVES THAT!" I don't think he's doing that.
So, talk to him. Tell him that you're okay with certain things but you do have boundries. And while your at it, suggest some things from a woman's stand point that he might suggest to his friend that his new bride might like if you're comfortable with it.
LOL! I mean, if you and your husband have an excellent sex life, share the knowledge and be proud!