The placement of a girlfriend's hand on boyfriend's upper abs for a photograph. It allows the girlfriend to turn her body in towards the boyfriend resulting in better looking angles for her own body as well as subtly communicating to photo viewers that, "He's all mine. Step off".
The change in pitch or tone of a man's voice when talking to their significant other. The girlfriend voice is characterized by a higher pitch and a more effeminate tone with speech patterns scattered with pet names and childish words.
This type of speech is usually frowned upon when used in the presence of other men. When another man uses this voice they will usually receive a fair amount of ridicule.