Sodomy is most commonly referring to anal sex. The word anal isn't appropriate when discussing sexual relations or acts, so the sodomy is used instead. Sodomy is illegal in most states I believe, which means you could get jail time for doing your wife in the pooper.
I get that No Pepper was joking on the nipple and elbow part, but was curious if he was serious about the oral gratification part. Just reminded me of elementary/middle school when you didn't know something about sex, and you asked someone else whe didn't know either but gave you a response anyways. For three years, I thought that "porking" someone meant sticking your finger in their nipple and not getting any milk back.:142smilie