An incomplete erection; often characterized by the partial flaccidity of one's penis. "Loiner" comes from the itching or burning sensation experienced in one's loins during a loiner.
I was so excited to have sex with Shea until I realized he could only pull off a loiner.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.