Line a baking sheet with parchment or waxed paper. Place yogurt in a small bowl. Use a toothpick to dip a blueberry in the yogurt, then tap off any excess. Use a second toothpick to push the blueberry onto the baking sheet. Repeat with more berries and the remaining yogurt (you should have enough to cover about a cup of berries). Freeze until firm, about 45 minutes. Serve immediately.