There's a few different "Icey Mikes", but one I've heard is where you take a shit, freeze it, and then when it's frozen a girl has sex with the frozen turd, just like a dildo.
Filling a condom up with water, much in the same style as a water baloon, freezing it and then using it for insertion, either on ones self or on another.
"My girlfriend loves playing with ice cubes, so I made an icey mike to really get her going..."
n. - The act of ejaculating into an ice cubetray and letting the semen freeze thoroughly, then using the ejaculate ice cubes in an unsuspecting guests drink.
man #1 - Let's pull an icey mike on Joe! He's coming over in 3 hours!
man #2 - Ok, I'll cum in the ice cube tray, you check to see if my ethiopian can opener is ready!
Using a frozen turd as a dildo. Sometimes a condom is used to form the feces into the desired shape, but this is optional, and dependant on the firmness and consistency of the stool sample.
My last girlfriend was a prude. She dumped me after I went to the freezer and showed her the Icey Mike I had planned for her...I mean us.