Because missionary is already -> missionary_position then reverse_missionary_position should be a valid thing to tag.

Yeah, I think this alias might work better the other way around.
Sure it's longer, but most other position tags are tagged as *_position. Might as well keep it uniform, at least that makes it easy to wildcard-search for those.

I agree with Genjar and Qmannn, aliasing reverse_missionary to --> reverse_missionary_position makes more sense. That way "reverse_missionary" becomes the shorthand version but the official version of the tag keeps the *_position just like most of the other sex position type tags. It's good to keep all of the same type of tag using a consistent tag-name pattern. It makes it easier to remember them, and possible to search them up using a wildcard.

So I think aliasing them is good, just need to flip the alias direction so that reverse_missionary_position becomes the final form of the tag.

The only reason I suggested this this way is because currently the tag is reverse_missionary and reverse_missionary_position is empty.