Dirty Soap
Dirty Soap is defined as the bar of soap in your shower you just used to wash your hands with after masturbating in the shower.
"Just throw that dirty soap out, it's no good anymore."
Dirty Soap Dispenser
When ejaculated in the participant's anus tell them to Bend over (rub hands together) wait till the load comes out like soap & rub it in like you're washing your hands with soap.
I gave her the dirty soap dispenser then I dried my hands off using her face.