To the original question:

Yes, it makes sense to me that above a certain size, the bigger you are, the more care you need to take. It is very possible to hurt your partner badly ... I know because I have done it.

To be a little more specific: if you are very thick, especially at the glans, preparation and care upon entry is essential. I imagine a slim but very long penis necessitates a totally different approach.

I discovered that both my thickness and my length can cause problems; but in the end, there is a difference. Taking the whole length is optional, but the girth can't be avoided.