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.

Potluck

A 'potluck' is a party or gathering where everyone brings a dish (i.e., salad, entree or dessert) to share with everyone else.

Example:
-What are you going to take to the potluck next week?
-My usual -- my grandmother's potato salad.