When one is, through possible over-indulgence of various substances, or by simply being a master in the art of ass-tappery, unable to cum despite trying incessantly.
One of the two different categories of whiskey dick, one a dysfunctional penis, the other, and overly functional dick.
"Dude she thinks I'm a god of the dick, I was uncumable"
1. not countable
2. incapable of having the total precisely ascertained
3. indefinitely large in number 4. an infinite number 5. too many to be counted
6. innumerable