In the past, couples have become stuck together during sex due to a rare condition called penis captivus Jason Reed/Reuters

A video has emerged online that apparently shows a prostitute attached to a dead man at the genitals. Though the incident is reported to have occurred somewhere in China, when and where exactly it happened is not known.

In the video, the dead man can be seen transported on a hospital stretcher covered by a blue sheet. However, it is quite difficult to figure out from the video whether a girl lay on top of the dead man or it was just a black coloured clothing of the deceased. When the hospital stretcher moves toward the ambulance, people can be seen looking on in horror.

According to The Mirror, the couple were taken to hospital where it is believed they were separated before the dead man was taken to the morgue.

In the past, couples have become stuck together during sex with a condition known as penis captivus. The medical condition is rare and occurs when the vagina clamps down on the penis much more firmly than usual, making it impossible for the penis to withdraw from the vagina. The condition, however, is not permanent and usually corrects itself after a time.

"When the penis is in the vagina it becomes increasingly engorged," Dr John Dean, a UK-based sexual physician, told the BBC. "The muscles of the woman's pelvic floor contract rhythmically at orgasm. While those muscles contract the penis becomes stuck and further engorged."

To separate the couple suffering from penis captivus, doctors administer an injection commonly used to dilate the uterus of pregnant women. Another method is tranquilising the man to make his muscles relax.

In 2009, it was reported that a couple got stuck together after suffering from penis captivus. The incident occurred in a small town in southern Philippines. The couple were stuck for more than 17 hours before they were separated.