Wikipedia

Rough trade

Often, the terms "trade" and "rough trade" are treated as synonymous. Often the attraction for the gay male partner is finding a dangerous, even thuggish, partner who may turn violent. That is not to say that people necessarily desire to be physically hurt, but the danger of seeking a partner in a public park, restroom, or alleyway may be exciting.

Another variation is in comparison to regular trade, rough trade is more likely to be working-class laborers with less education and more physical demands of their work, therefore with a body developed naturally rather than in a gym. They will have a less polished or Cleancut style than an office worker or professional businessman.

Gender roles

Usually, it is very important to the bi or straight identified partner that he maintain his stereotypical masculine identity and not be particularly emotionally available, nor cuddlesome, nor as the bottom. Often, with rough trade it is his stereotypical masculinity (i.e. bottom vs top, top vs bottom) being questioned that pushes him over the edge into physical violence.