Masculine energy. Time to man up, stand up (hee hee) and be assertive. The size and amount will be directly connected to how assertive you or someone around you is in real life. It can also suggest that you or someone around you is being a dick.
A removable penis is a good indication that you need to learn – or are in the process of learning – when it is best to be assertive and when it is best to be passive.