Calling your girlfriend a "little cotton-padded jacket" is a kind of intimate and warm address, which usually means caring for your girlfriend. This metaphor stems from the fact that a cotton-padded jacket is a kind of warm clothes, which can bring people a warm and comfortable feeling. Therefore, calling your girlfriend a "little cotton-padded jacket" is a way to express your love, indicating that you care and protect her like a warm cotton-padded jacket.

However, everyone feels and accepts in different ways, so whether it is appropriate to call his girlfriend "little cotton-padded jacket" depends on the specific situation and the feelings of both parties. The most important thing is to respect each other's wishes and personality, and choose appropriate names or expressions to convey your love and care.