Waste of (my) cum

There are two ways to use waste of cum.
1- In sub/dom relationships, you can call your sub partner a cum dumpster (a way to denigrate them). This frase is even worse. It can be interpreted that they aren't even worth being a cum dumpster. They are a "waste of cum". You can even add a "waste of my cum".
2- A way to refer to someone that is so worthless and useless that it's a waste that his/her/their father wasted their cum in making him/her/them.