It sounds funny but for real it ain't. Some gay men consider it a fetish... But it is really a terrible thing if it happens in a situation where the victim has little or no options. There are many reasons why a man would want to rape another man, but that is so vast we can't begin to delve into it. Please bear in Mind that when i talk of rape, i am not only refering to penetrative sex, but also to all other forced sexual acts that were not consentual.
