The Belgian says he takes notes before and after games.
He explained on Stadium Astro: "I think it started when I started played at Antwerp two years ago," he said. "I like to write things down before and after a game just to get my head into the right mindset. Sometimes if things don't go right, or you don't want it in your head, you just write it down to get it off your chest.
"I came up with it a little bit myself, but also got it from people talking about it as well, so I thought I would give it a try and it actually helped me a lot, so I still do it.
"Before a game, I write down a little bit about the opponent, about how they will play and put pressure on me. Also individual things, like key points I have to remember throughout the game."
Lammens continued: "Being a complete goalkeeper is something I take pride in. It's not just stop-stopping, it's coming out for crosses and helping the defence when the balls go behind them. My distribution as well, but what I'm most proud of is being able to play with my left foot and right.
"That makes it more difficult for the opponent to press me. Coming out for crosses is really difficult in the Premier League especially. I still like to do it a lot, but you need to protect yourself a little bit."