101st base 

When you have sex with a female while she is menstruating and the guy is doing a shit and getting mess all over the place.

guy 1: omg man i got to 101st base with my girlfriend last name

guy 2: *throws up*

101st base by Jubz! October 25, 2006

1001st base 

When two men clip open their ball sacks, allowing their nuts to fall out and dangle on your eyelids as you orgasm.

Chris: Hey, Katherine.
Katherine: Hi, Chris!
Chris: I 1001st base'd last night!
Katherine: Holy.. fuck..

1001st base by ChrisRawr June 2, 2013