The bulk update request #11383 is pending approval.

mass update micro_on_macro -> smaller_on_larger

Reason: I suggest creating an alias from micro_on_macro to smaller_on_larger, as it would give wider search results and also make tagging a bit easier.
Basically we could just type "smaller_on_larger" + "~micro" + "~macro" and get the same results as using micro_on_macro, if I've understanded the purpose of this tag correctly.
This could be used even if there's a character that can't be labeled as micro or macro, such as normal-sized rodents, or when it's unclear whether the character is actually micro or macro.
Also I don't think we need more than gender and body form related tags with micro and macro, anything else that is related small or big size could be labeled using "smaller" and "larger" terms.

The following tags could be used to define what "smaller" and "larger" are:

Here are some micro and macro tags that would still be available after these changes:

micro_on_macro is quite overused, often on posts that are just micro or just macro and not both (one character being exceptionally small or large, with the other being normal size relative to the background), or where there's an abstract or no background to say if one's large or the other's small and it's just two characters with extreme_size_difference.

That said, I don't think a smaller_on_larger tag is necessary, when extreme_size_difference (or size_difference) already exists. See topic #33834 with a pending BUR to alias micro_on_macro it to extreme_size_difference.

But using this tag, we could easily define which character is on which, or even exactly where the smaller one is positioned on the body, like on the shoulder. So with this tag we would get images and videos where someone is on top of someone.

kajokettu said:
But using this tag, we could easily define which character is on which, or even exactly where the smaller one is positioned on the body, like on the shoulder.

that-- that's not what *_on_* means when we use it like this. micro_on_macro and other tags with a similar format are paring tags, they're used for sexual or romantic interactions between characters.

Well, that was misleading for me at least. :D

I do think that an *_on_* tag might be nice, or otherwise a tag that will separate out when sexual interactions are happening between the characters with a size difference. While size_difference sex works for most posts, it a) does not cover sexual-but-not-sex interactions like handjobs and b) it's not super uncommon in vore for the characters who have a size difference to not be the ones interacting sexually:
post #4427872