Ancient Roman coins depict sundry sexual acts, but what were they for?

The Romans loved sex. The wrote graphic poetry about it, and scrawled x-rated graffiti on their city walls. They even emblazoned currency with depictions of sexual acts. But what purpose did this coinage serve? Fair warning: numismatic pornography after the jump – potentially NSFW. » 9/09/13 8:20am 9/09/13 8:20am