Brains!

"The sexual excitement we feel is related to the way we look at the other person. To clarify the notion of the objectness viewing position, we shall contrast it with another position referred to as tenderness. When we feel tenderness we look at the other's body as a whole. Our gaze spends most of its time in the head area and within the body boundaries. However, this position involves penetration for the other beyond the object characteristics. The body is experienced as a whole rather than as separate parts. It is perceived as embedded in its natural environment. For example, the reflection of sunlight off the hair, the grass one is sitting on, or the creek that one is near, all facilitate the tenderness orientation. There is a desire to place one's arms around and embrace rather than to use one's arms as instruments to maipulate the other." -James Barrel