Having Sex in the 11th dimension.
Usually involves Supergravity and M-theory. This results in having sex with your
lover of choice, then ending up with your grandmother 46 years ago, then in a different
galaxy, and finally you inexplicably become a tentacle monster that, for some reason, looks like a deviation of George W.
Bush.
As you drift into eternity, screaming every known and unknown language, you question why you bothered to look past 4th base. You become insane.
Then you
Die.
...In other words, a fun time. =D