If the angel listens carefully to the empathic riot of emotions coming off of both of them there might be hints. The tiny fluster of anger and jealousy from the one that looks about to start a fight at the mention of a kiss. It's not loud though, and easy enough to miss.

The two looked at each other, then the angel and frowned. "I don't know. Do we kiss different?"

The Ziggys are asking each other and uncertain. Maybe?