When one uses a scarf as a jizz bib, then returns the scarf to its rightful owner. The rightful owner then wears scarf around his/her neck, usually without knowing or ever finding out that it is stained with dried up man jam.
Roommate A: "Hey, I need to go out. Have you seen my scarf?"
Roommate B: "It was in my room so I hung it up in the closet."
Roommate A: "Cool." (Starts putting on scarf) "So where you been the last twenty minutes?"
Roommate B: *snorts/chuckles*
Roommate A: *tucks chin into scarf and sniffs* "Wait . . . did I just put on a pearl scarf?"
Roommate B: Yup!!!
Roommate A: No!!!!