the mark left in your bed after sex, or nick name for someone whos stupid
Man i got out of bed this morning and there was a huge fuck-stain on the sheets
John your a fuck-stain shut up.
A sploch left on a surface where sexual relations has been performed.
1)After they were done making whoopi, they noticed that there was a huge fuck-stain left on the table.
2)Eric is a fuck-stain.