I use a laptop cause I can't sit right for a desktop. I'm currently resting my laptop on my leg. I have my other leg tucked under that leg. The back of my chair is being used as an arm rest.
If this is a choice and you have the freedom to change, I suggest you focus now on ergonomic sitting habits. It will pay dividends later in life, and keep you out of the physical therapy office.
If this is not a choice, my apologies for being forward.
If this is not a choice, my apologies for being forward.