Why would a "simple definition" of "rape" be of any use to anyone? We can't reason from a "simple definition." All we can do with a simple definition is play semantic games, and I do not consent to that activity.

The law doesn't do "simple" definitons." Every legal definition explicilty or implicitly begins with "For purposes of ...." Simple definitions never work with that preamble. Because you are proposing that something be legally treated as "rape," you don't get to use a "simple" definition of the word. Whether I would use the term colloquially or metaphorically to condemn it ethically is a whole other question.

Labels are always deceptive, and the law never really looks at them. The question for the jury is not whether A has "raped" B; it is whether A has violated a statute that proscribes a behavior that A has done. The label is just a rhetorical tool.