Try this
Get a new sheet of dryer fabric softener, such as "Bounce". Just rub it all over the seat. I have leather in my truck and haven't had a shock yet, but when I owned a sedan with a cloth interior, I found this idea on the interent and tried it. It worked.
Also, after using the bounce sheet in the dryer, you can rub it on the clear portions of the radio display and instrument cluster, it really helps delay the dust on those surfaces. It has anti-static properties.
Also, try drying your jacket/coat with a anti-static sheet next time after washing. It's usually whatever you happen to be wearing that is the main contributing factor to the static buidlup when sliding out of the seat.