When someone posts images that aren't them on a dating site or app (see cat-fishing), but you still fly across the country to meet them, you end up sleeping with them, and get crabs.
"So I met this hot girl on Tinder, she sent me shots of herself in a bikini, we made plans for me to fly to Chicago to meet her, and then I got crabs. Textbook crabshacking."
"I couldn't help myself. He was so cute and sent me hipsterporn. I had to crabshack that fool."