A gender-neutral expression for masturbation or jacking off. Can be practiced, experienced, enjoyed or researched.
Yesterday my mum busted in while I researched the eigensex, entirely disrupting my physical experiment.
by paniq January 25, 2006
When one (typically a female) has a sexual intercourse encounter with a one eigendick (typically a male) and reaches the point of Eigenasm and cums everywhere
Yo Dubin I had Eigensex with that smut from chi-o last night....it was Eigengood..possibly the best Eigensex I've ever had.
by Eigensaw March 25, 2009