Living high on the hog

A person who is living 'high on the hog' is someone who living a very comfortable or wealthy life. Sometimes the person can actually afford to do so, and sometimes they are living beyond their means, living on credit cards.

Example:
-Wow, your brother's new house sure is beautiful! He's living high on the hog!
-Yes, he's had some very successful deals at work this past year.

To hog

'To hog' means to keep something all to yourself, so that nobody else can have any or use it. It's a common expression that kids use.

Example:
-Mom, she's hogging the computer again!
-Okay, you have 5 more minutes and then it's your sister's turn.