The action of doing something completely badass without the knowledge of being able to do so. It can happen if drunk, high, or simply really euphoric or excited.
Dude 1: Holy crap! Oh my god! Holy crap! Oh my god!
Dude 2: (To Dude 3) Jesus Christ! How many pills did he swallow?
(Dude 1 does a backflip)
Dude 3: Shit! He high AF dude, he be swonking!
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.