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
I went to 11th base with Jenn last night.
ןoן ¿¡ʎɐs noʎ pıp ʇɐɥʍ 'ǝpnp ʞɔnɟ!!!!?!!
Sex in the shower (with the shower on of course)
Girl 1: oo i got up to 11th base last night!
Girl 2: wow! what was it like?
girl 1: warm and wet