A fork of Rural Dictionary
A black eye or any other bruise received from a fight
After the boxing match Dave's eye was sporting a huge pain stain
The remorse one feels upon soiling another's linens with bodily excretions.
The night was going pretty well, until Anthony angered Melanie by ejaculating on her new Egyptian cotton sheets. Now he is feeling stain-pain.
NOTE: Not to be confused with Staind-pain, the extreme inner turmoil one experiences while listening to Break the Cycle.