A t-shirt depicting a howling wolf, usually accompanied by an image of the full moon. Typically worn by neckbearded Bob Seger look-alikes who play WoW all day in their mom's basement.
"Nate has been skipping class lately to play dungeons and dragons with Tony. What could be causing this?"
"Did you check his closet?"
"Full of wolfshirts."
"Ahh."
When a couple can do something with each other and for each other as opposed to an individual thinking only of themselves which could be defined as selfish. A couple is welfish.
After raising their elevenchildren, Fred and Freida looked forward to being welfish on a long deserved vacation.