20th base

giving yourself a blowjob and then your penis blows up.
"Dude I went to 20th base last night"
"Can you really?"
by Divi September 17, 2006
mugGet the 20th basemug.

18th base

growing a penis or vagina and having sex with yourself
"woh dude I went to 18th base last night"
"..."
by Divi September 03, 2006
mugGet the 18th basemug.