A redneck calls his doctor ...

After his 8th child is born. He says “doc, I need one of them vasectomy things!” The doctor says “ok you need to get an empty beer can and a firework”.

The redneck gathers the items and says “now what?” The doctor says “put the firework in the beer can, light it, and cover your ears.”

The redneck puts the firework in the beer can, lights it, puts the can between his legs and covers his ears ...

Edit: spelling correction (stupid phone)