The Swapping Game

Chen Yanhong and his wife Shiyin are both doctors at the hospital. As their married life slowly grows stale, he starts browsing swinger websites. Recently, at the invitation of psychology professor Xu Liming, he joins as a single man to watch the professor and his wife have sex... The first time he "spectates," Chen Yanhong watches Zhixian getting fucked by her husband Professor Xu until she's dripping wet, and feels an unprecedented thrill...