Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Someone: kindly explain to me detail how this is used? Also, does it stay under the mattress all the time (i donot have a box spring)? thx.
Document: I am disabled and changing my sheets is an ordeal causing lots of pain. I've only used it once so far, but it was great. I put it between the mattress and box spring and just push it in. I tuck the sheets in on either side of it. I then use it to push the sheets in even farther, all the way down one side at a time, to make the sheets taut. I had read a review saying you need two, so I bought two.
I was hoping this would help when putting the bedskirt over the box spring/under the mattress. It does lift the mattress slightly but it falls out when I am pulling the bedskirt up. Not recommended.
First, I had to lift the mattress to insert it, because I could not just push it in since I have a bedskirt draped over the box spring. Then, it often flips sideways and the mattress sags back down. I did not find this gadget very helpful. It's going to Goodwill.
I used this for the first time, yesterday. My husband's side was injured and he couldn't help me change the bedding. I purchased 2 of them, one for each of us. I left both on while doing the head. Then moved them to the foot of the mattress. They lifted the mattress just enough for me to slip my hand down and shove it under. These mattresses are SO HEAVY that I didn't think they would work! They were just wonderful.
After watching the video it looked real easy to use. If you have a bed skirt on your bed as I do, apparently this tool was not made to be used with one. When you try to push the lifter in under the mattress it takes the bed skirt with it. Also the cording around the edge of the mattress, when I try to push the lifter in, the cording makes it difficult to get the tool under the mattress.
This is the best thing for people with back problems or arthritis that still want to make their bedrooms look neat with the bed made daily. Using it the 1st time the sheets & blankets stayed tucked in for more than 10 days. I had my Mom get one & the couple that clean our house seem very interested also.
We have had a problem changing the sheets on our heavy mattress for a couple of years. My wife has arthritis and cannot lift the mattress. She saw the Bed MadeEZ in an arthritis article. We did a search on Amazon and found these. We ordered two and decided to try them. They worked GREAT. We have already recommended them to someone who cleans homes.
This might be the most pointless item I've ever drunk ordered. Yes, the mattress is heavy and I often wish I had someone to help me with it (okay, maybe I was drunk and recently single when I ordered this). But you can stick pretty much anything under the mattress to hold it up while you tuck in the corners.
This device is helpful except for someone who may not have the strength to get it under heavy mattresses in the first place.
I could tuck  the sheets on the corners without pain to my knuckles and the pain of lifting the mattress with one sore hand while tucking with the other.l. The lifter  kept the corner of the mattress up so i could use both hands without pressure on my fingers which are deformed with arthritis and extremely painful to the touch. I only gave it a four because at $30 plus iit was too expensive for someone on a very fixed income. I had to borrow money to buy it.
Answer: This is a tool to use when making your bed. With today's huge mattresses, it is difficult to get the fitted sheet to stay flat. With this apparatus,you push the sides of your fitted sheet under your mattress instead of using only your hands. Consider it an extension of your hands. And no, it does not remain under the mattress.