"I'm not dating Armand, I said ex. I used to date a vampire named Henry. He's not even on the Barge." Wait a minute...how did Arm--oh. Scent. Well, Tony wasn't going to bring up that he'd let Armand bite him if Spike wasn't going to say anything. "It also blocks black magic." And while you could argue some demons weren't bad, black magic directed at his room was a pretty unanimous bad thing.