Wrestling is a sport where two people (usually male) fight each other by grappling, each trying to throw and then pinion the other. In tag team wrestling, two pairs of people fight.
Wrestlers typically wear tight shorts similar to Speedos. This was originally to stop a wrestler grabbing his opponent's shorts. Also, wrestlers are often well-muscled.
Wrestling matches between gay men may be fair play or very one-sided (two or three against one). Part of the object may be to remove the opponent's shorts. Matches may involve handling the opponent's genitals and in extreme cases may resemble a cockfight.