"lol-in" is a term associated with the act of someone moving all their chips into a pot with something very weak, vulnerable, or obviously beaten in a hand of poker. It's basically moving "All-in" with a strong dickhead factor.
"I saw Bob make such a lol-in with 7h2h on a board of AsKs4s10sJc 6 handed yesterday. What a fucking donkey!"
"Hah! Really!? Could he even SEE the board!?"