This is, as it stands, the current definition of "rape" under the FBI:

Penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim.

This of course is a very stringent definition that looks to disinclude male victims of "forced to penetrate", as it defines it as solely penetration.

But then according to this blog post by Tamen, he contacted the FBI directly and they "confirmed" that the definition did confirm rape by envelopment:

I am happy to tell that Ms. Mary P. Reese, from the FBI’s CJIS Division’s Crime Statistics Management Unit confirms in an email that they consider rape by envelopment to be rape under the current FBI definition of rape, and that they’ll consider my suggestion in modifying documentation for the reporting agencies to reflect that more clearly.

Assuming this is the case, the definition doesn't reflect that and it would give actual male victims with the intention to report the wrong idea, so it doesn't wholly help much. But the definition does not reflect it, at all.

Say if the FBI's statistical tabulations on rape arrests, would that include "forced to penetrate" cases? (assuming there is a woman out there who actually has gotten arrested for doing such).