I found this device to be disappointing. Perhaps my cheeses were just not a good texture, but the trier rarely pulled out solid columns.
There's a technique to it for sure - don't turn & turn the trier trying to bore a hole as you'll make a mess. Young cheese it more difficult to get a clean sample.
My technique is hold it sideways, push straight in, turn 180 degrees (not a full circle), then pull out with a bit inward angle to help "grip" the plug....I watch new people try it and they make a mess -- practice makes perfect with using a trier. Nothing like pulling an aged cheddar plug.
I should add that I like a trier with a rounded shaft below the T handle because after sampling a few dozen blocks, the square shaft starts irritating my hand but the round one doesn't.