Air Quotes

The other day while talking with students, I inadvertently used air quotes when referring to one of them. This particular student is known for his no holds barred critiques of other students' work, and he also happens to be getting married soon. So, after he made yet another frank comment to a peer, I halfheartedly affirmed it by telling the recipient:  yes, you should follow [blank's] advice since he's the "love expert." Like I said, I did the air quotes without even thinking.

Shortly after, another student piped up and asked what they meant. Before I could reply, someone chimed in:  I read that Americans do that when they want to emphasize something. At that point, all eyes were on me, and I had no option but to confess:  Yes, we do make that gesture to emphasize something, but often it's to indicate sarcasm. [Pause] Which was what I'd intended.  

A lesson on sarcasm is a tricky one to explain to native speakers, let alone non-native ones. Think I'll look for some mittens over the weekend to minimize the potential for another air quote flare up.