Why can't countries/unions pump and dump government bonds?

Seriously, why can't **countries or unions pool their financial strength and buy lots of bonds**? They could advertise it, like **"The EU is buying 20% of Venezuelan bonds,"** and encourage other institutes to buy too. **In the end, the country sells all or most of its shares and makes money out of "thin air."** It could invest the money in education and infrastructure to **help its people without taxing them heavily**. Yes, I know it's **pretty unethical**, but **why aren't we seeing this happen?** There must be a reason I'm missing.