Oversteer and understeer are just what they say.
Oversteer: the car turns (steers) more than is expected.
Understeer: the car turns (steers) less than is expected.
To make things more complicated, front wheel drive and rear wheel drive have some opposite handling characteristics, however higher tire pressure adds more steering grip to the axle
it is on. That is front axle
= oversteer, rear axle
YouTube - Car Handling - Grip, Oversteer & Understeer explained by Tiff Needell
Everyone gets used to the handling of the car they drive. If you change the ratio of tire pressure front axle to rear axle, you can affect how the car handles. Front wheel drive and rear wheel drive are discussed in the video. AWD, or All Wheel Drive avoids the power over/understeer of the single axle powered car.
Apparently Subaru desires an understeer condition when towing because of the danger of the TV sliding out and the trailer consequently jackknifing.
I recall hearing a screaming sound and then observing a large white van sliding driver side first sideways down the highway with a utility trailer actually pushing the van down the road. The van had just negotiated a left curve, so I assume he had over compensated for an oversteer condition to the left and caused an oversteer to the right and once the jackknife occurred and the trailer took over, he was helpless to do anything but ride it out.