When the phallus is in that often uncomfortable state of half-formed erection. Usually softens if the possesser requires it to be hard, and vice versa if he is in an uncomfortable situation for an erection.
Wearing tight jeans, Bob sucks in his stomach in the hopes that his semirection retreats into placcid-hood.
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.