Taking viagra for the extended-play, going the whole weekend long. A way to find out if you are crossing the line of taking too much when you can't "finish" half the time or you have to finish yourself. Selfish sex a holics love to have viagrathons.
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.