Free Haircut

Alright listen up, buttercup. See, when people have cancer they go through chemo and that makes their hair fall out. So they shave their heads to avoid dealin' with that mess. The joke is suggesting you call a cancer hotline so you can pretend to have cancer and get a free haircut. It's funny because it's dark and insensitive, and it exploits a serious illness for a cheap laugh. You wouldn't get it.