When one sexual partner connects the rectum hole with another, and either one eject's feces into the other's rectum. The other partner, who has received the feces, will excrete it back into the partners, along with her own. This will happen back and forth, making the Bulgarian Subway Train
The Bulgarian Subway Train was very gross, so said the viewers. They also listen it as being 'vile' .
by Hamachis October 23, 2010