shore hardness

When your dick gets hard while you're at the beach.

When a man gets an erection while at the beach. Typically while wearing swim trunks.

"Hey man come look at the crab I found."

"Can't dude, I got shore hardness."

"oh, yeah I saw that milf walk by too."

"How do you keep from getting shore hardness when you go to those nude beaches?"

"Easy, I just jack off before."