To be caught up in a state of excessive excitement, obsession, yearning or overindulgence; either specifically sexual, or in a more general sense.
“Man, have you seen Cindy lately?”
“Oh yeah, that girl gives me a yard-long hardon.”
“This new project they have us on is a pain in the ass!”
“Yes it is. But if I were you, I’d quit complaining and get back to work. All the brass have a yard-long hardon for this thing.”
“I’ve got to get my son off his butt and outside this summer. The boy has a yard-long hardon for pizza and Playstation, and if he doesn’t get active, he’s gonna be fat as an elephant.”