Me too, seems like I can't get the leverage right. I wish I could cause my back just kills me.

I've tried to do that many times and I just don't seem to be able to. I don't think I get as good a look at what's going on by sitting and trying to cut. What I have done, though, is to put my cutting mat on my kitchen counter, which comes up to about waist high for me, and it works great. My back will still bother me a little, just from standing, however, it's so much better than trying to bend over and cut. Hope this helps.

Oh, yes. I have a table to the left of my machine with a cutting mat on it. I cut, lay out pieces for blocks, and trim on it. I have my big ironing board right behind me so I can just turn and press, too. I have a nice adjustable secretary chair on wheels I can just rotate and roll around.

Cannot sit while cutting so I put bed risers under the legs of my table. Raises the table to a comfortable height(sp)and my back feels much better and I can cut longer without any discomfort.

NEVER!
i have found the ruler will slip when i do that. i personally think you need to be "above" the fabric and board to cut properly. i wish i could though. sometimes my back needs to be rested on a chair!

I do when I'm doing small cuts or using templates but I'd rather stand. However, I know several quilters who are very comfortable sitting to cut.

I sit and cut my fabrics/blocks all the time. For longer cuts
I need to stand up or I don't get an accurate cut.

I totally agree with that, otherwise I can't see what I'm doing.

If you are able to stand and cut on a table that is higher than a normal table, you will have much more accuracy. I have Sally Collins precision piecing book and this is her advice. I usually stand for most of my cutting except for paper piecing. Has certainly improved my accuracy.

I stand when I cut blocks, I don't think you can get good pressure on the rulers when cutting while sitting down.