SWMBO uses a wheelchair and of late, transferring to and from our sofa has become a bit too exciting :(
One of the issues is that it's a genuine leather sofa. And despite the leather feeling smooth to the touch, it appears to take on an infinite coefficient of friction when arse touches it.
Have tried a few materials to aid "slippiness" but they are equally stuck fast under weight (SWMBO weighs under 70Kg ...)
We're investigating transfer boards, but I wondered if there was anything that might be suitable for a sliding cushion so that she is closer to the chair for the transfer.