look up any word, like dirty sanchez:
 
1.
Shooting a woman and fucking the bullet hole
Guy: Dude, got to 17th Base last night
Friend: did she live?
by pHyR3 August 23, 2011
 
2.
Group sex with your parents and your parents parents.

If one or more of the participating parents is dead and
requires exhumation before participating then 17th base
becomes: 103453rd base,103454th base,103455th base,103456th base,103457th base,103458th base,103459th base,103460th base,103461st base,103462nd base,103463rd base,103464th base,103465th base,103466th base,103457th base depending on the combination exhumed and then group
fucked with.

Me: "While I was at grandma's place she suggested we spice things up a bit and move from boring old 3rd base to full on 17th base."
Friend: "Dude, isn't that pretty far out even for you?"
Me: "Yeah but at least they are all alive, you know."
by Sean the Snorf Dude August 19, 2006