No you cannot kill someone by poking them in the belly button, that is a myth. The only way that could happen is if they Had a Hernia in their belly button and you ruptured it. If you stabbed them or shot them in the belly button it could possibly kill them. However a simple poke or twirl in their belly button will not harm them. A hard poke would hurt, but it would not be fatal.
It is really easy to kill someone just shoot them in the head with a gun and then rape them.
Poking somebody anywhere is dangerous. The navel is not especially sensitive.
with a poking head motion
Poking them with a fork.
YES
Well it depends, if you like someone you might be poking them to get their attention, but if they are your friend you might just be poking them to cheer them up or tease them.
Someone could hit you in the head with it i guess.
no
No. this would not kill you quickly. the only thing that could kill you is the loss of blood. It is common for someone to die with a shot in the head but the chances are 2/5 that you will survive
yes
No, an empty can does not have enough mass per volume to kill someone, but they might chase you down and kill for throwing it at them!