Someone who holds an item for another when that person does not have a hand free (they are carrying too many items). Holdilocks is typically used at a bar when a woman needs to look in her purse for something and needs a friend to hold her drink! It is a term of endearment towards the person who is holding the drink/item for a friend. (Noun)
"Jenna, will you be my holdilocks?" Jen says passing her drink to her friend. "I need to put my lipstick on." Jen, in the middle of the dance floor, begins digging in her purse for her lipstick as Jenna holds her drink.
"Laura, will you be my holdilocks?" Karen says passing her drink to her friend. "I want to light this cigarette."