sliperoo 

When you accidentally slip and penetrate your significant other.

Guy: "Whoops!"
Girl: " WHAT THE FUCK ARE YOU INSIDE ME?!"
Guy: " Oh sorry hun must have just been a little sliperoo"

Girl: "OH in that case i completely understand"
(both proceed to laugh)

sliperoo by BIGCOXES January 13, 2014

Slipperoo 

1. When a man and a woman are fucking the bed, but not each other, and the male counterpart is about to rape the woman, he shouts out "Slipperoo!"

2. A magical rapist kangaroo.

Man: "Want to go fuck that bed with me?"
Woman: "Hmmm...Okay."

(One minute later)
Man: "Woopsi-daisy. Slipperoo!"
Woman: "Oh, no! Why do I keep falling for this?"

Slipperoo by Mouth Organ March 13, 2008

Sliparoo

When you slip your penis in her vagina when in bed together ..... unbeknownst to herself.

Phil came in from the pub last night, and in an attempt to avoid an argument with amy, he performed the sliparoo so as to not wake her up

Sliparoo by Simpson Eire December 11, 2011