The state of the man in the photo in the link above has to do with how he was embalmed. The erection is there because the veinous pressure when the formaldehyde was inserted was high. I read about a trial in the U.S. in the last few years where some employees at a funeral home were charged with some sort of malicious mischief from abusing dead bodies. They were torquing up the pressure on dead men to cause erections, though the pressure was always released later for the regular viewing and funeral purposes. The employees probably did it for comparison purposes--who knows--but it was considered inappropriate enough to get them charged and convicted.

SRS