Before one try to understand the term Bull, one should know what is cuckolding to get familiar on what I'm talking about.
There are so many husbands who get turned on by the idea of their wife having sex with another man. In this fantasy we have threesomes, group sex, cuckolding.
Some husbands are more interested in watching their wife having sex with another man rather than personally being involved in the sexual act. This is known as cuckolding. The husband here is usually the cuck and the other man is known as the bull.
There is also another case where the other man simply likes to watch husband and wife in the sexual act and not being sexually involved. In that case, the other man is the cuck.
