A foot fetish.
When the skin of your earlobe is attached to you skin on your head (upper jaw), it is called an attached earlobe. Earlobes that hang more freely are called unattached. They earlobe itself it not attached to your head, it is only attached to the bottom of your ear.
Schediaphilia, is the word for that fetish. It is also know as toonophilia.
Fetish for small spaces is called claustrophilia.
There isn't really a special name, probably because it is not very common. It is simply called an elbow fetish.
Remembering that fetish means replacing normal object of sexual desire with the fetish object, I suggest you are seeing the gun as a phallic symbol.
External ear called pinna
The knobbly bit on your ear is called the tragus.
name the tissue on the earlobe
How do you fix a split earlobe?
Watersports
That is too normal to be called a fetish. Most men are intensely aroused by the female buttocks and anus.