PhiloTV

I am curious about a special effect that appeared during the two Kalinda sex scenes. For a few frames in each, we were presented with the image of an undulating red blob. It reminded me of the effects used to dramatize disease processes in House, but it didn't appear to be recognizable tissue and didn't really do anything but undulate. What is this thing: spider venom? Carnality Incarnate? an impending stroke? an STD? What? Thanks.