The one-sentence version
A rear support sling is a wide, soft band that goes under the back half of your dog, with a handle you hold, so you take the weight his back legs can’t.
Sling, harness, or wheelchair?
A sling is the light-assist option: you steady him on walks and stairs, his legs still do most of the work. A lift harness is the structured version, with clips and padding, for lifting a dog into a car or up a flight of stairs. A dog wheelchair carries the rear end entirely on wheels, for dogs whose back legs are done working.
Most dogs need only the sling or harness stage. The wheelchair is the last stop, not the first.
When it earns its keep
Recovery weeks after knee or hip surgery. Arthritis that makes the last block of the walk look like a marathon. Senior dogs who wobble on hardwood. And the walk that used to be easy but now needs a spotter.
On the walk
Hold the handle low and level. Let the front legs lead; they’re usually fine. Stop when the dog stops, not when you reach the corner. Keep early walks short and end them while he’s still having a good time, so tomorrow he wants to go again.
First-time tips
Let him sniff the sling. Feed a treat through the first few fittings. Two minutes indoors before you take it to the street. Dogs decide fast whether a thing is scary, and the first impression is the one that sticks.
The boring but important part
Buy machine-washable, and buy two if the sling becomes part of daily life, so one is always clean. Check the belly skin weekly under the band; rubbing turns into sores on thin-coated dogs.
The gear
A dog rear support sling and a dog lift harness with a handle are the two pieces above.