The only way to make Dusparce usable is to give it a paraflinch set.
Dunsparce @ Leftovers
Ability: Serene Grace
EVs: 252 HP, 4 Def, 252 Sp. Def
- Headbutt/ Rock Slide
It relies on luck, because Dunsparce is so frail that it needs the right opportunity to set up, unlike say Jirachi or Togekiss who have good bulk. Glare's recommended because it'll hit ground types as well.