Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: I would like to know before I buy it....first is it a firm topper?  I don't want something that I sink into.
Document: I have an uncomfortably firm mattress that I hoped would soften over time. When I was fed up and ready to just buy a new mattress I thought I'd try this topper and WOW. The first night of sleeping with it on felt like a brand new luxury bed. It's amazingly soft, but still gives support. I have read that some foam toppers trap in a lot of heat but this one miraculously stays nice and cool.
This product is amazing! It's like sleeping on a cloud. I bought an extra firm mattress a couple of years ago, thinking it's the best for my bad back and herniated discs-boy was I wrong! I have had terrible mid back pain and hip pain upon waking every morning for YEARS. I did not want to buy a new mattress, as our was still new.I read the reviews and decided to try this and I'm really glad I did.
My fiance suggested to buy this for his mom. At first she did not like it (I believe due to it being something new and a change..haha), but after a couple days she changed her tune and complimented on how nice it was. She says she finally got a good nights sleep without waking up in the morning with pain. Told him how much she appreciated him suggesting it!
Fixed overly firm mattress. Would definitely buy this product again. I like the convenience of separate topper and mattress.If buying one, consider getting fitted sheets with deeper pockes
Based on the Amazon reviews, I purchased this so as to arrive at the same time as a new mattress and box spring (purchased locally). My thinking was that I would buy the firmest (non-pillow top) mattress that I could find and then put this topper on. This worked even better than hoped and for the most part I am able to sleep through the night on my sciatica side - something that I hadn't been able to do for many years.
Love this. It does have a smell, it takes about a month for it to go away. It is an odd smell not something that fills your bedroom but when you lay down you will get whiffs of it. I would smell the topper and there would be nothing so I think it has something to do with body heat? We found the topper to be firm and helped with our hip &  back pain. Neither my husband  nor myself felt we we were down in the topper.
You will have to develop abs of steel just to turn or roll yourself out of bed. The marshmallow cloud that was once beckoning us has now become a quick-sand monster. When my Husband is not in bed I will literally be in my own little sink hole. When he joins I will go up like in a waterbed and level out with him. At times we will sort of fall into one another. This isn't what you want when you are sharing a bed!
?or their existing bed is so shot that it would take a miracle to make it better, or maybe they have different expectations from most of the people who love this topper. I once read on the internet about pillowtop beds,and it was only someone else's opinion, a person who worked in the mattress industry for years - he said it was better to buy a very firm mattress and buy your own thick memory foam topper to have a great sleeping experience - time will tell for me.
I would recommend this over and over again, I don't want to get out of bed in the morning. My ONLY con....is I had to buy expensive sheets, because my mattress is already 17" deep and this added another 3" .....so I found some sheets with spandex sides that go up to 24" deep and they were not cheap, so that was another $100 added to my total, but I still have 100% pleased.
I was looking for something that would give me relief. I happen to see these in Big Lots, of all places, and talked to two different guys who have them on their beds and for the money I decided to try it. The first night I slept 5 hours and never changed positions, when I woke up I felt so rested I couldn't believe the difference.
Answer: You will sink into it.  It feels firm, at first.  After lying on it for a few minutes you will sink into it.