There are tags like miniboy and giant for incredibly small and incredibly big humanoids, but besides that there doesn't seem to be many tags for any other size humanoid.
This is a specific genre of sex post involving short statured (>2 foot, roughly <3 or 4foot) humanoid creatures.
post #4102644 post #4790308 post #5409174 post #4123294
There's also the opposite with >8foot to <12foot humanoid creatures.
post #3736677
height difference wasn't designed for these unrealistic situations, and a tag like that wouldn't distinguish these two types.
A solution would be to have something like short stature and tall stature, or small humanoid and big humanoid.
- This would not apply to literal children.
- If the size of the character can't be inferred from the image it wouldn't need the tags (e.g. post #5328711 post #5382975).
- Ideally the two tags would also have gendered variants because the sex is very different depending on which of the gender is larger.