How are cock rings supposed to fit?

[Hugo20]

View media item 13271031

 

[captain_juicyprecum]

What u think is this fitting good to me

View media item 14543481
View media item 10271021

 

[hardnshavd]

I found these, takes the guesswork out of it to get a perfect fit! Sizing Rings (Includes 11 rings, all sizes 1" - 2 1/4" for Glans & Cockrings) — Cockrings Online