Slippery Whistle 

When a male and female are getting intimate and the girl is giving the guy a hippity handjob. Then the female, without the male's knowlege, hops on top for a slippery suprise, often making a slide whistle noise.

Hey guys, that bitch just gave me a Slippery Whistle!

I was shocked when that girl gave me a Slippery Whistle in bed!

Slippery Whistle by l69lSlipperyWhenWet November 6, 2010

Slippery Whistle 

When a girl is performing felatio, the guy pushes too hard on the back of the girl's head and she slides up the shaft gagging and blowing out like a slide whistle. This is usually combined with a bit of vomit and/or saliva, making the shaft slippery.

I got pissed that this chick wouldnt deep throat, so I slippery whistled her, and now I got puke all over my boxers.

Slippery Whistle by Big Unca Mike September 19, 2007

Slippery whistler 

When a woman is in prime orgasm and the pussy farts so knarly that she can play the harmonica with this musical whistle

Dude last night I was having sexual relations with your sister, she started screaming and bam! Out came a slippery whistler. It was like music to my ears.

Slippery whistler by Whitelavenderr June 29, 2016