A Swedish study exploring the connection between different types of social touch and their meaning has found an interesting link between what happens in the brain when viewing a sensual touch (during a romantic scene) as with experiencing the same type of touch in real life.

The skin as a social organ
The study focused on dynamic touching, a type of touch characterized by continuous movements over the skin that can be repetitive and are often slow, like caressing or stroking.

Male and female participants were placed in an MRI, and their field of vision was restricted while the blood flow to their brain was monitored. Participants were then stroked along their forearm with a delicate brush at various speeds without being able to see their forearm (removing visual stimulus).

Researchers monitored blood flow in the posterior insular cortex (PIC) of the brain (involved in empathetic situations, processing emotions, and even orgasms). For the participants in the study, this portion of the brain was much more stimulated by the slower movements than the rapid ones, showing an intimate caress to be more stimulating to that area of the brain that a quick slide across the arm.

Visual stimulation and the brain
For the second part of the study, participants were shown video of a forearm being stroked that utilized the same technique while their brains were monitored in the MRI. These video clips were shown randomly between each participant's own physical caresses.

Similar to the first study, the brain scan showed no lag in blood flow to the same brain area. This led researchers to suggest that witnessing a sensual touch has practically the same impact on that part of the brain as receiving one.
"The aim was to understand how the brain processes information from sensual contact, and it turned out that the brain was activated just as quickly when the volunteers got to watch someone else being caressed as when they were being caressed themselves," says India Morrison, the first author of the paper. "Even when we are only watching sensual skin contact, we can experience its emotional meaning without actually feeling the touch directly."
This suggests that seeing a sensual event during a romantic movie has the same on your brain as real thing.  These findings have been published as Vicarious Responses to Social Touch in Posterior Insular Cortex Are Tuned to Pleasant Caressing Speeds in the Journal of Neuroscience.