Do you mean the other partner went along with it out of fear, confusion, embarrassment, compulsory heterosexuality, intoxication, or disability? Yes, it is still rape because those traits nullify perceived consent. In legal terms, however, there are instances where juries decided it wasn't. This is partly why giving/waiting for an explicit YES in casual sexual encounters is so important. And, you know, there's also the whole making sure my partner feels good aspect of it.