Ruff.
Sparky
Because dogs can't whistle. (X-post from r/dadjokes)
Piston
To get to the other slide.
Ruff!
The sandpaper doesn't scream when I rub it's face on wood.
RUFF!
Spot. What do you call a dog who lays on a golf course Ruff. What do you call a dog who just got run over Rhody.