My pigs tend to pee at the bottom of the ramp, so to protect the carpet I use kitten litter trays at the bottom of the larger ramps. All I do is lift the ramp up and then put it back down with the bottom of it actually in the toilet.
I stuff the toilet with hay to tempt them to go into the litter tray to pee and poop, although it is natural for them to stop at the bottom and do their stuff even without hay!