Penis-dry is an word used to describe something that someone tried to dry off, but still remains annoyingly moist. This comes from the fact that after bathing and showering, the penis always seems to be difficult to get fully dry quickly without accidentally chaffing or the like.
"Someone go towel off the dog again! He's penis-dry!"
"No matter how long I left that blanket in the drier, it always comes out penis-dry."
"His hair is so thick, he always comes into school penis-dry."
"Check out that fat old person. Its pits are penis-dry. Nasty."