Similar to a security blanket; when one partner reaches around and grabs the breast of the other partner for comfort. This can be done either consciously or subconsciously.
"Mike, you always hold my boob when you're sleeping...what is it, your security boob?"
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug