Petroleum is a gas and jelly is the hardened gelatinous juice of fruit, meat and others. And petroleum jelly is a collection of solid heavier products like crude oil. It is used in industrial or mechanized lubrication of moving parts and vacuum systems.
But petroleum jelly can also be used for health applications. It can seal capped lips and moisturize dry skin. It is also used to soften corns and calluses. Burn can be relieved by applying petroleum jelly on the burnt area after it has cooled down to keep the skin from drying. Itching and other irritations can also be relieved.
Petroleum jelly is meant for external use only and injecting it in the penis is dangerous.
Got the photo from the Internet.